Most chordates are ________.
A. vertebrates
B. mammals
C. invertebrates
D. None of the above
Answer: A
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Which of the following does not tend to promote speciation?
A) the founder effect B) gene flow C) natural selection D) polyploidy E) disruptive selection
The electron transport system
A. requires a membrane. B. utilizes the nuclear membrane of eukaryotes. C. utilizes the mitochondrial membrane of prokaryotes. D. generates a concentration gradient of protons. E. requires a membrane AND generates a concentration gradient of protons.
__________ are symbionts with young roots that enhance a plant's ability to absorb mineral ions from
soil. Fill in the blank(s) with the appropriate word(s).
Some scientists are trying to develop a vaccine that would prevent cancer. What is an important consideration?
A. The natural killer (NK) cells already perform this function, which cannot be enhanced. B. Since cancer cells have self-marking MHC molecules, they cannot be attacked by the immune system. C. It is not possible-vaccines can only protect against viruses or bacteria. D. Antigen selection would be critical, due to danger of the body's immune system attacking its own healthy tissue.