5. Which statement is a specific example of how artificial selection is
used in society?
A. Pesticides applied to plant-eating beetles yield a pesticide-
resistant population of beetles.
B. Two racehorses with desirable traits are bred to produce a
superior racing horse.
C. Genes are spliced from a bacterial cell and inserted into a cell of
an apple tree.
D. The nucleus of a cow's skin cell is inserted into an egg cell of a
female cow.

B. Two racehorses with desirable traits are bred to produce a superior racing horse.

Explanation:

Artificial selection is also called selective breeding. In artificial selection, two organisms having desirable characters are allowed to breed with each other in order to produce a specie having good characteristics or better from their parents in many ways. For example, two racehorses which contains desirable traits are allowed to breed to produce a better horse.

"1. it should be, it has been for about 20 years, and it's really not much different in the end than breeding animals to have particular traits. there are always concerns about genetically engineered animals/plants affecting the environment in unexpected negative ways, but i can't think of an example where the fears didn't turn out to be baseless.  

first, as you point out, it would be a great advance in pharmacology, to be able to tailor drugs and their doses to me. the pros involve better medical treatment. the cons involve privacy issues like insurance companies denying coverage to people with genetic risk factors. looking at dna markers wouldn't affect the frequency of genetic diseases, but it would allow detection of them earlier. and ok, actually i suppose that if people used this information to avoid having children with genetic diseases, some might decrease in frequency."

the cladogram shown here shows similarities and differences among several classes of vertebrates. anatomically, the four have limb structure as their common ancestor. we might separate the mammals from the other three classes because they a) divergent; do not lay eggs b) identical; are warm-blooded c) varied; a four chambered heart d) homologous; have mammary glands