A notochord is
A. a strip of cartilage that forms a back and tail in all vertebrates.
B. a stiff dorsal supporting rod that is replaced by the vertebral column during development.
C. a stiff ventral supporting rod.
D. replaced by the nerve cord during development.
E. All of the choices are correct.
Answer: B
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Biological diversity is composed of what three levels?
A. trophic diversity, ecosystem diversity, and species diversity. B. ecosystem diversity, species diversity, and process diversity. C. genetic diversity, function diversity, and process diversity. D. genetic diversity, species diversity, and ecosystem diversity.
Which of the following is true about genetically modified foods?
a. They have been genetically altered by adding genes from an alternate organism. b. All of their genes have been sequenced, so their entire genome is known. c. Portions of their DNA have been manipulated, and genes have been moved to different chromosomes. d. They have undergone natural selection, and some important genes have been inserted
Using the illustration above and the
assumption that half of a plant's sperm and eggs are a and half are A, one can predict that the chance of sperm a meeting egg A at fertilization is a. 1/2 ? 1/2. b. 25 percent. c. one out of four. d. 1/2. e. all of these EXCEPT 1/2.
Photoreceptors are found in the
a. lens. b. ciliary body. c. iris. d. retina.