Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key


Play button


Play button




Click to flip

262 Cards in this Set

  • Front
  • Back
The creation of offspring carrying genetic information from just a single parent is called
asexual reproduction.
Which one of the following is a difference between sexual and asexual reproduction?
Sexual reproduction is more likely to increase genetic variation than is asexual reproduction.
With the exception of identical twins, siblings who have the same two biological parents are likely to look similar, but not identical, to each other because they have
a similar but not identical combination of genes.
Sister chromatids are
tightly linked together at a centromere.
Eukaryotic cells spend most of their cell cycle in which phase?
The process by which the cytoplasm of a eukaryotic cell divides to produce two cells is called
If the S phase was eliminated from the cell cycle, the daughter cells would
have half the genetic material found in the parental cell.
Which of the following occurs during interphase?
cell growth and duplication of the chromosomes
Looking into your microscope, you spot an unusual cell. Instead of the typical rounded cell shape, the cell has a very narrow middle separating two bulging ends. It sort of looks like the number 8! Then you realize, this is a cell
undergoing cytokinesis.
Which of the following is a feature of plant cell division that distinguishes it from animal cell division?
A cell plate forms.
When animal cells are grown in a petri dish, they typically stop dividing once they have formed a single, unbroken layer on the bottom of the dish. This arrest of division is an example of
density-dependent inhibition.
As a patch of scraped skin heals, the cells fill in the injured area but do not grow beyond that. This is an example of
density-dependent inhibition.
A benign tumor differs from a malignant tumor in that a benign tumor
does not metastasize.
Which one of the following is not a function of mitosis? Mitosis helps organisms? A. grow. B. regenerate lost parts. C. reproduce asexually. D. repair tissues. E. All
Which of the following is a difference between mitosis and meiosis?
can reveal alterations in chromosome number.
Examine the following sentence. "Where is the cat?" Which one of the following variations of this sentence is most like a chromosomal deletion?
Where is cat?
Cancer is not usually inherited because
the chromosomal changes in cancer are usually confined to somatic cells.
The genetic material is duplicated during
the S phase.
Both mitosis and meiosis are preceded by
Which one of the following statements best represents the theory of pangenesis developed by Hippocrates?
Particles called pangenes originating in each part of an organism's body collect in the sperm or eggs and are passed on to the next generation.
Alleles of a gene are found at __________ chromosomes.
the same locus on homologous
Imagine that we mate two black Labrador dogs with normal vision and find that 3 of the puppies are like the parents, but one puppy is chocolate with normal vision, and another is black with PRA (progressive retinal atrophy, a serious disease of vision). We can conclude that
the alleles for color and vision segregate independently during gamete formation.
Using a six-sided die, what is the probability of rolling either a 5 or a 6?
1/6 + 1/6 = 1/3
Assuming that the probability of having a female child is 50% and the probability of having a male child is also 50%, what is the probability that a couple's first-born child is female and second-born child is male?
A carrier of a genetic disorder who does not show symptoms is most likely to be __________ to transmit it to offspring.
heterozygous for the trait and able
Dr. Smith's parents have normal hearing. However, Dr. Smith has an inherited form of deafness. Deafness is a recessive trait that is associated with the abnormal allele d. The normal allele at this locus, associated with normal hearing, is D. Dr. Smith's parents could have which of the following genotypes?
Dd and Dd
Many genetic disorders of humans are caused by
recessive alleles.
The vast majority of people afflicted with recessive disorders are born to parents who were
not affected at all by the disease.
Which one of the following is an example of incomplete dominance in humans?
Imagine that beak color in a finch species is controlled by a single gene. You mate a finch homozygous for orange (pigmented) beak with a finch homozygous for ivory (unpigmented) beak and get numerous offspring, all of which have a pale, ivory-orange beak. This pattern of color expression is most likely to be an example of
incomplete dominance.
The expression of both alleles for a trait in a heterozygous individual illustrates
A person with AB blood illustrates the principle of
Genetic testing can reveal
a person's chances of developing a disease.
What is the normal complement of sex chromosomes in a human male?
one X chromosome and one Y chromosome
How many sex chromosomes are in a human gamete
What is meant by the statement that "male bees are fatherless"?
Male bees develop from unfertilized eggs.
Why are sex-linked conditions more common in men than in women?
Men need to inherit only one copy of the recessive allele for the condition to be fully expressed.
Mendel conducted his most memorable experiments on
A color-blind woman mates with a man who is not color-blind. All of the sons and none of the daughters are color-blind. What is the best explanation of this result?
The gene for color vision is linked to the X chromosome.
Which of the following people conducted experiments that demonstrated that DNA is the genetic material of bacteriophages?
Hershey and Chase
When a T2 bacteriophage infects an E. coli cell, what part of the phage enters the bacterial cytoplasm?
only the DNA
The way that genetic material of a bacteriophage enters a bacterium is most like the way that
a drug is injected with a hypodermic needle.
The monomers of DNA and RNA are
The shape of a DNA molecule is most like
a twisted rope ladder.
DNA replication
uses each strand of a DNA molecule as a template for the creation of a new strand.
If one strand of DNA is CGGTAC, the corresponding strand would be
When one DNA molecule is copied to make two DNA molecules, the new DNA contains
50% of the parent DNA
Which one of the following sequences best describes the flow of information when a gene directs the synthesis of a cellular component?
DNA RNA protein
The transfer of genetic information from DNA to RNA is called
Experiments have demonstrated that the "words" of the genetic code (the units that specify amino acids) are
three-nucleotide sequences.
We would expect that a 15-nucleotide sequence will direct the production of a polypeptide that consists of
5 amino acids.
Where do transcription and translation occur in prokaryotic cells?
in the cytoplasm
Translation consists of which of the following?
the conversion of genetic information from the language of nucleic acids to the language of proteins
Any change in the nucleotide sequence of DNA is called
a mutation.
A physical or chemical agent that changes the nucleotide sequence of DNA is called
a mutagen.
The envelope of a flu virus
helps the virus enter the cell.
HIV delivers its greatest damage to
white blood cells.
A friend accidentally sends an email to you that contains a computer virus from his computer. Without knowing it, you add the virus to your computer when you open the email. This process of spreading the computer virus using emails is most like which of the following processes?
One type of virus that infects bacteria is called a(n)
Aristotle believed which of the following?
species are fixed (permanent) and do not evolve
Lyell's book Principles of Geology, which Darwin read on board the H.M.S. Beagle, argued for which of the following concepts?
The Earth's surface is shaped mainly by forces that act gradually and are still acting.
The unifying theme of biology is
Which one of the following did Darwin discover that led him to suspect that species in the Americas were more closely related to each other than to species elsewhere?
The South American fossils he collected were more similar to living South American species than to fossils from other continents.
Which one of the following best expresses the concept of natural selection?
differential reproductive success
Malthus's essay led Darwin to which of the following generalizations?
All organisms produce more offspring than their environment can support.
Broccoli and cabbages are both descended from the same wild mustard and can still interbreed. The existence of these two vegetables is an example of
artificial selection.
Which of the following provides evidence that vertebrates evolved from a common ancestor? A. homologous structures
B. the common development of pharyngeal pouches in an embryonic stage
C. the presence of similar genes
D. similarities in protein structure
Student Response E. All of the choices are correct.
Darwin found that Galpagos animals resembled species of the South American mainland
more than they resembled animals on similar but distant islands.
Which one of the following represents two structures that are homologous?
the wing of a bat and the flipper of a whale
A population is
the smallest unit that can evolve.
A change in the relative frequencies of alleles in the gene pool of a population is called
Genetic drift resulting from a disaster that drastically reduces population size is called
the bottleneck effect.
A population of 1,000 birds exists on a small Pacific island. Some of the birds are yellow, a characteristic determined by a recessive allele. The others are green, a characteristic determined by a dominant allele. A hurricane on the island kills most of the birds from this population. Only ten remain, and those birds all have yellow feathers. Which of the following statements is true?
The hurricane has caused a population bottleneck.
Thirty people are assigned to live in a spaceship that is exploring other galaxies. The journey will take several hundred years and will be completed by the descendants of these crew members. The gene pool of the population on this ship when it returns is most likely to reflect
a founder effect.
An individual who does not finish all of a prescribed antibiotic is
adversely affecting the health of all individuals who, in the future, may be exposed to that bacterial strain.
Fitness increases when an organism
adversely affecting the health of all individuals who, in the future, may be exposed to that bacterial strain.
Fitness increases when an organism
passes on a greater proportion of its genes to the next generation.
Long-legged cheetahs are well adapted to catching prey. The ancestor of the cheetah is believed to have had relatively short legs. According to Darwinian views, the evolution of long-legged cheetahs is best explained by
directional selection.
The primary purpose of the 1831 voyage of the Beagle was to
survey the waters around the southern coast of South America.
What was Darwin's job on board the Beagle?
ship's naturalist
A biological species is defined as a
population or group of populations whose members have the potential to interbreed and produce fertile offspring.
Two species that occasionally mate and produce zygotes, but which have incompatible genes that prevent the resulting embryo from developing, are separated by
hybrid inviability
Two species interbreed occasionally and produce vigorous, fertile hybrids. When the hybrids breed with each other or with either parent species, however, the offspring are feeble or sterile. These species are separated by
hybrid breakdown.
Two species that sometimes mate and produce vigorous, sterile offspring are separated by
hybrid sterility.
Frequently, a group of related species will each have a unique courtship ritual that must be performed correctly for both partners to be willing to mate. Such a ritual constitutes a type of
behavioral isolating mechanism.
Which one of the following is an example of a hybrid that is both vigorous and sterile?
a mule
The Monterey pine and Bishop's pine inhabit some of the same areas of central California. The Monterey pine releases pollen in February, while the Bishop's pine does so in April. This is an example of __________ isolation.
A mountain range divides a freshwater snail species into two isolated populations. Erosion eventually lowers the range and brings the two populations together again, but when they mate, the resulting hybrids all produce sterile young. This scenario is an example of
allopatric speciation.
Speciation without geographic isolation is called __________ speciation.
Organisms having more than two complete sets of chromosomes are said to be
Sympatric speciation was first discovered by __________ while studying genetic diversity in primroses.
de Vries
The emergence of numerous species from a common ancestor that finds itself in a new and diverse environment is called
adaptive radiation.
In their 30-year studies of Darwin's finches, the Grants have discovered that when the ground finch and cactus finch occasionally form hybrids, these hybrids
can only survive during wet years when there are plenty of soft, small seeds.
The fossil record reveals that frequently, speciation occurs
in a relatively short time, perhaps just 50,000 years.
The __________ suggests that speciation occurs in spurts.
punctuated equilibrium model
Punctuated equilibrium differs from the gradualism model because in punctuated equilibrium
All of the choices are correct.
Most of the evidence from the fossil record supports the position that
evolution occurred in huge leaps and bounds.
A study of human evolution compared the features of an adult human skull to the skulls of an adult and infant chimp. At the end of the study, it was clear that the adult human and infant chimp shared many more features than the adult human and adult chimp. This study suggests that humans evolved by the process of
According to island biogeography, the farther an island is from the mainland, the
lower the rate of colonization.
According to island biogeography, the larger an island, the
greater the species richness.
Which of the following correctly states the relationship between dinosaurs and birds?
Biologists now widely accept that birds were descended from dinosaurs.
By studying fossils in strata from many locations, scientists can learn about
Plants and animals first became established on land during the
Which of the following eras is often called the "Age of Reptiles"?
If all of Earth's history were compressed into an hour, humans would first appear about
one second ago.
The technique called radiometric dating is based on
the measurement of certain radioactive isotopes contained in fossils.
When the continent of Pangaea first split apart, it formed
a northern landmass called Laurasia and a southern landmass called Gondwana.
Which of the following lines of evidence suggests that lungfishes evolved while Pangaea was intact?
fossil lungfishes have been found on every continent except Antarctica
The continents and seafloors together form a thin outer layer of the Earth called the
Which of the following phenomena can be caused by continental drift? A. mountain formation
B. volcanoes
C. earthquakes
D. the merging and breaking up of continents
Student Response E. All of the choices are correct.
Geologists call the forces within Earth that cause movements of the crust
plate tectonics.
How many periods of mass extinction have occurred in the last 600 million years?
Which of the following is the process by which species not closely related may come to resemble one another if they live in a similar environment?
convergent evolution
Structures that evolved from the same structure in an ancestor are
Which of the following is written correctly? The scientific name of the human species is
Homo sapiens.
A mother comes home to find cookie crumbs on the kitchen counter and children who are not interested in eating any dinner. She asks if they ate cookies and they deny doing so. Instead, the children explain that a pack of dogs broke into the home and ate the cookies. Then the dogs left. Now the kids don't feel like eating. The mother doubts the story, using the principle of
The three-domain system
subdivides the prokaryotes into 2 different domains.
In the three-domain system, the eukaryotes are represented
only by the Domain Eukarya.
__________ first appeared during the Precambrian era.
__________ were the dominant plant life during the early Mesozoic era.
Which of the following organisms first gave Earth its oxygen-containing atmosphere?
When the Earth first formed, it had an abundant atmosphere of hot hydrogen gas What happened to this atmosphere?
It escaped into space because the Earth's gravitational field was not strong enough to hold it.
Earth's second early atmosphere, the one produced by outgassing of volcanoes and other vents, is thought to have consisted mainly of which of the following components?
water vapor, nitrogen, carbon dioxide, and hydrogen sulfide
In the experiments of Miller, and those of other scientists, it was shown that
amino acids and sugars could be produced from the inorganic components thought to have been on the primitive Earth.
Pairs of rod-shaped bacteria are called
You culture the dried soup from a 4,000-year-old cooking pot found in an Egyptian tomb and obtain a distinctive species of prokaryote. You immerse a test tube of these bacteria in boiling water for several hours, but the colony grows back. This species is probably
The short, thin appendages that help prokaryotes adhere to surfaces, such as rocks or cells, are called
Which of the following organisms are common soil inhabitants and grow in the form of a filamentous mass of branching cell chains that superficially resembles a fungus?
The most common sexually transmitted disease in the United States is caused by
Which one of the following causes food poisoning and typhoid fever?
A patient comes to the doctor because of a large, bull's-eye-shaped, red rash that has a clear patch in the center. Originally there was an insect bite in the middle of the rash. The patient lives in a rural area of the United States where deer are common. Which of the following diseases will the physician immediately suspect?
Lyme disease
Which of the following have greatly reduced the incidence of bacterial diseases?
All of the choices have reduced the incidence of bacterial diseases.
Which one of the following groups of organisms has had a greater impact on the environment and on biological evolution than all other forms of life combined?
The term for a close association between two or more species is
While on a camping trip in Southern California, you drink untreated mountain water. After a few days you develop persistent, chronic diarrhea. Microscopic examination of a fecal sample from you is most likely to reveal
Which of the following causes African sleeping sickness?
Plasmodium, the organism that causes malaria, is a(n)
Which one of the following groups are large multicellular organisms deliberately consumed by humans?
brown algae
You collect a protist off a rotting log and grow it in a petri dish containing E. coli, which it eats. For a while the protists multiply as single cells. Then the E. coli run short, and the protists aggregate to form a clump, which rises up to become a stalked structure with a globular head. What kind of protist have you got?
a cellular slime mold
Gas exchange in plants occurs through structures called
In plants, vascular tissue made of dead cells that transport water and minerals from the roots is called
In plants, vascular tissue that consists of living cells that distribute sugars throughout the plant is called
Mosses are included in a group of plants called the
The dominant types of seed plants today are the
conifers and angiosperms.
Which of the following are adaptations that help plants live on land?
All of the choices are correct.
The type of life cycle seen in plants is called
alternation of generations.
Ferns and mosses are similar because both
have sporophytes that produce haploid spores.
The key step in the adaptation of seed plants to dry land was the evolution of
wind-dispersed pollen.
The great depositions of organic material during the Carboniferous period led to
the production of coal.
Which part of the life cycle does a pollen grain represent?
a male gametophyte
The ripened ovary of a flower, which is adapted to disperse seeds, is called a(n)
Angiosperms disperse their seeds by producing
All of the choices are correct.
Fruits, vegetables, corn, rice, and wheat are all examples of
Plants dependent on nocturnal pollinators typically have flowers that
are highly scented.
Which one of the following is an essential part of most fungal reproduction?
The last common ancestor of animals and fungi
was flagellated.
What kind of entity is a lichen?
an association between a fungus and cyanobacteria or green algae
Central Amercian leaf-cutting ants
cultivate fungal gardens on the leaves.
Which characteristic is shared by algae and seed plants?
cell walls
The most recent evidence revealing the relationship between modern humans and Neanderthals is based upon
Prehensile tails are found among
New World monkeys.
Natural populations of lemurs are found only in
A prehensile tail is like an opposable thumb in that both
are used for grasping.
The apes whose behavior most resembles human behavior are the
Which of the following are known to use tools?
Individuals of which ape group spend almost all of their time on the ground, instead of in trees?
The only nonhuman apes that establishes monogamous relationships, with mated pairs remaining together for life, are the
The animals most closely related to humans are the
Human DNA and chimpanzee DNA
differ by about 1%.
Humans and chimpanzees last shared a common ancestor about
5-7 million years ago.
Of the following, which is the first distinctively hominid trait to appear in the fossil record?
upright walking
Clearly bipedal hominid fossil footprints date to about __________ years ago.
3.5 million
Studies of the Y chromosome suggest that modern humans diversified about __________ years ago.
Human skin color likely represents a compromise between
the need to block UV radiation that destroys folate and the need to synthesize vitamin D
Which one of the following is a major milestone of human evolution that is most directly related to the development of culture?
prolonged parental care
Agriculture is considered the __________ major stage of human culture.
Today, much of the Fertile Crescent is
Overgrazing by domestic animals likely led to the
creation of deserts.
In which of the following ways do you differ greatly from your ancestors of 100,000 years ago?
You have access to a larger store of accumulated knowledge.
Since 1980, the rate of multiple births has nearly doubled. Which of the following most likely contributes to this increase?
increased use of fertility drugs
Which of the following is an aspect of asexual reproduction that is sometimes disadvantageous?
It produces genetically uniform populations.
Hermaphrodites are animals that
possess both male and female reproductive systems.
Reproductive systems with external fertilization are most common in
aquatic animals.
Where in a woman's reproductive tract does fertilization most often take place?
in the upper third of the oviduct
What moves the human egg through the oviduct?
the beating of cilia in the oviduct
Why are human testes located in an external sac rather than in the abdominal cavity?
so the testes can be kept cooler than the body's interior
Why are human testes located in an external sac rather than in the abdominal cavity?
so the testes can be kept cooler than the body's interior
Men who take very long, hot baths probably
produce fewer sperm.
None of the choices are correct.
In human females, the ovarian cycle begins when
the hypothalamus stimulates the anterior pituitary to increase its output of FSH and LH.
Animals that experience estrus typically
mate only during short periods of the year.
Which of the following types of pathogens cause sexually transmitted diseases that are generally not curable?
The best way to avoid the spread of STDs is
joins two haploid sets of chromosomes and activates development in the egg.
The yolk sac of humans
is evidence of humans' relationship to egg-laying vertebrates.
What is gestation?
The human embryo's first blood cells arise in the
yolk sac.
At which of the following gestational ages does a developing human first look obviously human and not like other vertebrate embryos?
9 weeks
At which of the following gestational ages does a developing human first look obviously human and not like other vertebrate embryos?
9 weeks
At about what point in gestation does the fetal heartbeat become audible by stethoscope and the fetus's sex evident?
12 weeks
Sperm develop in the
The largest plant on Earth is a
2,500-year-old Sequoia tree in California.
The vast majority of living plant species are
Dicot floral parts usually occur in multiples of
four or five.
The vegetative (i.e., nonreproducing) structures of flowering plants include
stems, leaves, and roots.
A plant stem modified for nutrient storage is called a
Which one of the following structures is found in plant and animal cells?
Which one of the following structures is found in plant and animal cells?
Photosynthesis occurs in
Which of the following types of plant cells help regulate the movement of carbon dioxide into and out of a leaf?
guard cells
The chief function of root hairs is to
increase the surface area for absorption of water and minerals.
Most trees and shrubs continue to grow year after year. Such plants are known as
The increase in girth (width) of trees occurs as a consequence of
secondary growth.
How many layers of vascular cambium will there be in the trunk of a 10-year-old tree?
The male organ of a flower is the
In a typical flower such as a magnolia or rose, the flower parts that play the main role in attracting the notice of animal pollinators are the
Flowers bear seeds in protective chambers called
Which of the following flower parts produces male gametophytes?
How does the sperm of an angiosperm reach the egg?
via the pollen tube that grows through the carpel tissues from the pollen grain deposited on the stigma
A seed is a mature
How many chromosomes are there in a maize embryo cell nucleus as compared to a maize endosperm cell nucleus?
two-thirds as many
A mature ovary, specialized as a vessel that houses and protects seeds, is a
What force is responsible for the cohesiveness of water?
hydrogen bonding between water molecules
The two main forces that move water upward in xylem are
transpiration and root pressure.
A hot, dry summer will reduce crop yields in part because
carbon dioxide uptake and photosynthesis are slowed because the stomata close more frequently to prevent excessive water loss.
Under which of the following weather conditions would transpiration be most rapid?
hot, dry weather
Dew, fog, high humidity, and rainfall mostly affect vascular plants by
reducing the transpiration rate.
If a plant is kept in the dark, we would find that
the stomata continue their daily rhythm of opening and closing.
In general, we can say that fluids are
pushed along in phloem sap and pulled along in xylem sap.
Which of the following is an essential macronutrient for plants and is obtained directly from the atmosphere?
Micronutrients function in plants mainly as
Which of the following is the set of plant macronutrients that make up about 98% of a plant's dry weight?
carbon, oxygen, hydrogen, nitrogen, sulfur, and phosphorus
Which one of the following is usually not found in fertile topsoil?
If you examine the soil profile revealed by a fresh road cut through a grassy rise, which of the following features will you probably find in the B horizon?
an abundance of fine clay but not much organic material
On a trip to the Southwest, you and a friend collect some pinion pine seeds. Your friend also gathers a small bagful of dirt from under a pinion tree. Back home, both of you plant your seeds in commercial sterilized potting soil, but your friend adds a spoonful of the collected dirt to each of her pots. Her seedlings do better than yours. Which of the following is the likeliest reason?
The dirt from the Southwest probably contained fungi able to establish a micorrhizal association with the seedlings' roots.
The relationship between a plant and mycorrhizal fungi is best described as
Legumes, such as beans or peas,
form mutualistic associations with nitrogen-fixing bacteria.
Carnivorous plants are more likely to occur in acid bogs because
organic matter decays so slowly there.
Carnivorousness in plants is primarily an adaptation for
growing in soil poor in usable nitrogen.
An example of an organism that parasitizes a host plant is
__________ increase the surface area of roots.
Root hairs and mycorrhizae
When a nursery worker pinches off the terminal buds on a young chrysanthemum plant to make it grow bushy, which of the following plant hormones is mainly responsible for stimulating branching?
a cytokinin
The most reliable way to stimulate branching in a plant is to
remove the apical bud.
Shoot branching is controlled mainly by the relative levels of
auxins and cytokinins.
Fruit that forms on an unpollinated plant in response to a hormone will lack
Cabbages are biennial plants that produce a head the first year and a flowering stalk the second. The growth of the flowering stalk, called "bolting," involves rapid elongation of an already-formed stem. Which of the following substances is likely to be immediately responsible for inducing bolting?
a gibberellin
Which of the following hormones is/are produced in the apical meristems of shoots and roots?
Yellow sweet clover is a roadside weed found throughout much of the United States. A yellow sweet clover plant growing in which of the following situations would probably contain the highest concentration of abscisic acid?
along a desert road in southern Utah just after 4 weeks of dry weather
What prevents a seed released in the fall from germinating immediately?
abscisic acid
At the end of the growing season, you have some green tomatoes that you want to pick and ripen in the house. To ripen them as quickly as possible, you should
place them in a sealed plastic bag with a ripe banana.
In many grocery stores, fresh fruits are sold prebagged in plastic bags dotted with holes. The main function of the holes is to
facilitate diffusion of ethylene away from the fruit.
Experimental plants that were sent up in space shuttle missions did not exhibit all their normal tropisms. Which of the following responses would you expect a plant in a space shuttle not to exhibit?
A plant that responds to touch with a change in growth movement is exhibiting
Mimosa plants spread their leaflets during the day and fold them at night. Your uncle decides to find out whether his mimosa's leaf movements are controlled by a biological clock. Which of the following experiments would you recommend?
Put the plant in a dark closet at nightfall. Check on the plant in the morning about 10 hours later, while the plant is still in the closet. If the leaves are open, a biological clock is indicated.
Which of the following events in a vegetable garden is never directly affected by light?
fertilization of egg cells
Christmas cactus is a short-day plant that usually blooms in the winter. Which of the following strategies might get it to bloom for the 4th of July?
leaving it in a dark closet all night and part of each morning during June
A plant's first line of defense against infection is
its epidermis.
The study of how animals use plants to medicate themselves is called
The first human medicines from plants probably resulted from
early humans watching what plants were eaten by wild animals.
Leaves that survive the winter tend to be
small and narrow.
What is the specific term that refers to seasonal changes in the relative lengths of night and day?