Explanation
Correct answer: B.
Choice B is the best answer because it most logically completes the text’s discussion of artificial light at night (ALAN) and the common clownfish (A. ocellaris). The text indicates that researchers found that when A. ocellaris is exposed to low levels of ALAN, spawning frequency and egg fertilization aren’t significantly affected but hatching is completely inhibited—that is, the eggs never hatch. Therefore, if A. ocellaris were to settle only in regions where the fish would be regularly exposed to low levels of ALAN, their eggs would stop hatching and their reproductive success would be at risk.
Why the other choices are wrong
Choice A
Choice A is incorrect because the text indicates that exposure to low levels of ALAN had no significant effect on egg fertilization for A. ocellaris, so there’s no reason to expect there would be any significant difference in rates of successful egg fertilization between areas with low levels of ALAN and areas without ALAN.
Choice C
Choice C is incorrect because the text doesn’t discuss the particular effects of low levels of ALAN on any species of coral reef fish besides A. ocellaris. For this reason, there’s no support in the text for the idea that the reproductive success of A. ocellaris is more greatly affected by the presence of low levels of ALAN than the reproductive success of other species of coral reef fish is.
Choice D
Choice D is incorrect. The text does indicate that A. ocellaris incubation was most strongly affected by low levels of ALAN, but it doesn’t indicate that there was a greater effect on spawning frequency than on egg fertilization; in fact, the text states that there was no significant effect on either.