7. The correct answer is photosynthesis.
Autotrophs are organisms which produce food for themselves-from simple to complex molecules. In the case of photosynthesis, producers (plants or some algae) use the light energy to produce complex organic compounds (carbohydrates, fats, and proteins).
8. The correct answer is primary consumers.
Since the pioneer species are usually autotrophs because there is no other source of energy except light energy in the early stages of succession (after the eruption). Most likely, the primary consumer will appear next because they feed upon producers.
9. The correct answer is: they are different populations of fish.
Those two different kinds of fish have unique adaptations that enable them to survive and live in distinct environments. It is most likely that molecular changes underlie adaptation and speciation of those fishes.