After reading the paragraph below, answer the questions that follow.
The herbicide atrazine is a known endocrine disruptor to the development stages of several animal species, including fish, reptiles, and amphibians. Scientists interested in studying long-term effects of exposure to atrazine on mating behaviors compared an all-male population of sexually mature African clawed frogs (
Xenopus laevis) exposed to atrazine (Atz) to a sexually mature population of African clawed frogs not exposed to atrazine (Con). Amplexus is defined as the mating position of frogs.

When considered together, Parts A and C demonstrate
◦ that testosterone levels are lower in nontreated frogs.
◦ that all frogs in the experiments were male.
◦ a possible explanation for the effect of atrazine.
◦ a lack of relationship between successful mating and testosterone levels.