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.

-Supposed additional tests conducted on these two groups of frogs indicated that atrazine-treated frogs have lower fertility rates than nontreated frogs, even though both groups have adequate sperm content. What might be concluded about long term-effects of atrazine?
A) Small body weight and decline in fertility in atrazine-exposed males will have a direct negative impact on populations of African clawed frogs.
B) The inability to compete for females and the decline in fertility in atrazine-exposed males will have a direct negative impact on populations of African clawed frogs.
C) Testosterone levels of atrazine-exposed males directly impact female frogs' copulation behaviors.
D) Non-atrazine-treated frogs are more likely to show an increase in body weight and testosterone levels in the presence of sexually mature female frogs.

Question

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.
 
-Supposed additional tests conducted on these two groups of frogs indicated that atrazine-treated frogs have lower fertility rates than nontreated frogs, even though both groups have adequate sperm content. What might be concluded about long term-effects of atrazine?
A) Small body weight and decline in fertility in atrazine-exposed males will have a direct negative impact on populations of African clawed frogs. 
B) The inability to compete for females and the decline in fertility in atrazine-exposed males will have a direct negative impact on populations of African clawed frogs. 
C) Testosterone levels of atrazine-exposed males directly impact female frogs' copulation behaviors. 
D) Non-atrazine-treated frogs are more likely to show an increase in body weight and testosterone levels in the presence of sexually mature female frogs.

Quizplus · Accepted Answer

The lower fertility rates in atrazine-treated frogs suggests that exposure to atrazine can negatively impact mating behaviors and fertility in male African clawed frogs. This could have a direct negative impact on populations if male frogs are unable to compete for females or reproduce successfully. There is no indication in the paragraph that body weight or testosterone levels are directly impacted by atrazine exposure, or that non-atrazine-treated frogs show any specific behaviors in the presence of sexually mature female frogs.

The Herbicide Atrazine Is a Known Endocrine Disruptor to the Development