Answer:
A. decreases as you move away from the equator in both terrestrial and marine ecosystems.
Step-by-step explanation:
Most of the population of animals in both terrestrial and marine ecosystems lives near the equator because temperature is favorable and there is more food available in the form of producer (plants). When we go away from the equator towards poles, the temperature decreases and also food is unavailable in large quantity so the population of organisms decreases in both terrestrial and marine ecosystems.