In paragraph 6, why does the author compare the bluegill sunfish to the pumpkinseed sunfish? A. To show that nesting has different costs and benefits for solitary organisms than it has for organisms living with other members of the same species B. To provide evidence that social nesting is usually superior to solitary nesting C. To argue that, in closely related species, the feeding organs of solitary organisms usually differ from those of social organisms D. To show that closely related species can be social or solitary depending on which behavior better enables them to fight off predators