Although numbers of animals in a given region may fluctuate from year

Question 3

You are correct in pointing out that the passage only discusses the density-dependent theory in the case of growth rate decreasing as the number of animals increases. However, the overall purpose of the passage is to present theories explaining the "relative constancy" of animal populations in a given region. With this broader purpose in mind, it is not a huge assumption to apply the density-dependent theory to a case in which the number of animals is decreasing and infer that the growth rate will increase.

In addition, by using the process of elimination it is clear that no other answer choice supports the density-dependent theory at all. Even if (A) requires a small leap of logic, it is without a doubt the correct answer because the other answer choices can be definitively eliminated.

Question 4

Question #4 asks what function "epideictic behavior displays" serve. In other words, what is the purpose of these behaviors?

In the last paragraph the author explains that, according to the epideictic theory, "organisms have evolved a “code” in the form of social or epideictic behavior displays, such as winter-roosting aggregations or group vocalizing; such codes provide organisms with information on population size in a region so that they can, if necessary, exercise reproductive restraint."

So, animals have developed certain behaviors in order to spread information about population size. The purpose of spreading this information is to allow organisms to limit the population by having fewer offspring.

Let's first look at (A):

The passage discusses winter-roosting aggregations as an example of an epideictic behavior, but the purpose of this behaviors is not "determining roosting aggregations." As discussed above, these behaviors are used to allow organisms to make the decision to have fewer babies. So, (A) does not reflect the function served by epideictic behaviors.

Now take a look at (D):

This aligns nicely with our analysis above -- the function of epideictic behaviors is to allow organisms to "exercise reproductive restraint" if necessary. (D) is the correct answer to question #4.

Question 5

To answer this question, we need to find out how the author feels about the challenge posed to the Wynne-Edwards theory.

The relevant piece of the passage is the very last sentence: "However, Wynne-Edwards’ theory, linking animal social behavior and population control, has been challenged, with some justification, by several studies."

Here, the author reveals that he/she thinks that the studies challenging the Wynne-Edwards theory have "some justification." In looking through the answer choices, we need one that reflects this somewhat reserved support for the challenges to the theory.

The only answer choice that fits the bill is (B), "qualified acceptance." The author accepts that the challenge is justified, but qualifies (or adds conditions to) this acceptance with the modifier "some."

I hope that helps!