____________ are disorders that involve impairments in the sexual response pattern, either in the desire for gratification or in the inability to achieve it

The fact that some researchers interested in human developmental processes often examine rats is an indication that they believe in

a. stem cell flexibility b. the ethical treatment of animals c. apoptosis d. phylogenetic continuity

What part of the chromosome is thought to be the location where cells lose their ability to replicate?

a. telomeres b. free radicals c. antioxidants d. atherosclerosis