CST 10th Grade Life Science

Which of the following explains why natural selection acts on the phenotype of an organism instead of its genotype? A Phenotypes directly influence the interaction of an organism with its environment. B Genotypes do not change except by the process of transcription. C Genotypes change in direct response to habitat changes. D Phenotypes can be inherited by offspring.

A Phenotypes directly influence the interaction of an organism with its environment.

How do nutrients, absorbed by the small intestine, travel to the individual cells of the human body? A The nutrients are absorbed from the small intestine into the blood and move through the circulatory system to the body cells. B The nutrients move from the small intestine directly to the liver and then move through the lymphatic system to the body cells. C The small intestine forces the nutrients into the kidneys, where the nutrients are then dissolved in fluids used by the body cells. D The body cells send nerve impulses indicating a lack of nutrients to the small intestine, and the small intestine sends the nutrients back to the cells.

A The nutrients are absorbed from the small intestine into the blood and move through the circulatory system to the body cells.

Which of the following is an example of an antigen that might be recognized by the immune system of an individual? A a viral protein B a fat molecule C saline solution D oxygen molecule

A a viral protein

Which three human-body systems coordinate to cause an arm to move? A nervous, muscular, skeletal B respiratory, muscular, digestive C skeletal, circulatory, immune D digestive, nervous, circulatory

A nervous, muscular, skeletal

What process is necessary for the inherited traits of an organism to be passed along by sexual reproduction? A mitosis B meiosis C mutation D fission

B Meiosis

Which of the following is a source of genetic variation within a species? A cloning B mutation C selective breeding D natural selection

B Mutation

The inheritance of a trait in humans is best described as being determined by A a single allele. B one or more pairs of alleles. C one pair of chromosomes. D the sex chromosomes of the offspring.

B One or more pairs of alleles.

Which of the following sets of organisms would be found in a wetland ecosystem? A tortoise, lizard, fly B salamander, mosquito, frog C moose, seal, lemming D lion, giraffe, beetle

B Salamander, mosquito, frog

Which of the following cell types is formed by meiosis? A muscle cells B sperm cells C skin cells D blood cells

B Sperm Cells

A particular allele in mice is lethal in homozygotes. Heterozygotes, however, develop normally. Why does this allele remain in the population? A Homozygous mice pass the allele to their offspring. B The recessive allele is masked in heterozygotes. C Natural selection selects for the homozygous individual with normal alleles. D Natural selection selects against the heterozygous individual.

B The recessive allele is masked in heterozygotes.

Which of the following pairs provides structural support for a human? A skin and blood B bones and muscles C spine and heart D brain and nerves

B bones and muscles

Which of the following levels of organization best represents the sequence from smallest unit to largest? A cell, organism, organ, tissue B cell, tissue, organ, organ system C cell, organism, tissue, organ system D cell, tissue, organism, organ

B cell, tissue, organ, organ system

The purpose for giving a person a vaccine is to A introduce chemicals that destroy viruses. B stimulate an immune response. C prevent inflammation. D cure a disease.

B stimulate an immune response

Which of the following lacks a nucleus? A a plant cell B an animal cell C an amoeba D a virus

C An Amoeba

How is natural selection in the evolution of long necks in giraffes best explained? A Shorter-necked giraffes were killed by long-necked giraffes. B Giraffe necks grew longer because of the bone structure of the animals. C Giraffes with longer necks survived because they were better suited to the environment. D Long-necked giraffes mated only with other long-necked giraffes.

C Giraffes with longer necks survived because they were better suited to the environment.

Rainfall in a tropical region is below average for 10 consecutive years. Insect species adapted for dry conditions are much more plentiful at the end of the 10 years. Which of the following statements best explains the increase in the population of these insects? A Biodiversity in the region has increased due to the dry conditions. B Insects with a high tolerance for dry conditions have migrated out of the region. C Natural selection has favored insect species with a high tolerance for dry conditions. D Natural selection has selected against insect species that are adapted for dry conditions.

C Natural selection has favored insect species with a high tolerance for dry conditions.

Which structure stores most of the genetic information? A mitochondrion B lysosome C nucleus D tail

C Nucleus

The diet of white-tailed deer consists primarily of shrubs. Sika are another species of deer that eat both grasses and shrubs. After an extended drought period, why might the sika population be favored over the white-tailed deer population? A Sika require less food than do the white-tailed deer. B Sika require more water than do the white-tailed deer. C Sika have more food sources than do the white-tailed deer. D Sika have fewer food sources than do the white-tailed deer.

C Sika have more food sources than do the white-tailed deer.

As a person exercises, carbon dioxide (CO2 ) levels in the blood increase. This causes the nervous system to signal which of these systems to respond? A digestive and immune B immune and respiratory C respiratory and circulatory D circulatory and endocrine

C respiratory and circulatory

The jackrabbit population sometimes decreases dramatically. One possible explanation for this decrease is that the coyote population has increased. This explanation is a scientific A conclusion. B experiment. C hypothesis. D law.

C. Hypothesis

Which of the following organelles releases energy from sugars? A ribosomes B vacuoles C chloroplasts D mitochondria

D Mitochondria

Which of the following processes allows the cells of an organism to use carbon from the environment? A mitosis B fertilization C transpiration D photosynthesis

D Photosynthesis

Which of the following best describes the inheritance of a sex-linked trait? A a recessive allele carried by females that affects only males B a dominant allele carried by females that affects only males C an allele carried on the Y chromosome that can affect both males and females D an allele carried on an X chromosome that can affect males or females

D an allele carried on an X chromosome that can affect males or females

Skeletal structures are common between two animals of different species. These structures probably exist because both species A have a common food source. B live in the same environment. C have survived until the present time. D are related to a common ancestor.

D are related to a common ancestor.

Which of the following organelles use carbon dioxide to produce sugars? A vacuoles B ribosomes C chloroplasts D mitochondria

D. Mitochondria

Which of the following structures is not found in bacteria? A ribosome B cytoplasm C cell membrane D nuclear membrane

D. Nuclear Membrane