For the carbon cycle and the nitrogen cycle to function properly, which organisms must always be present?
a) decomposers
b) herbivores
c) parasites
d) predators

I think the answer is "A"

Explanation:

The hint said very small. Mushrooms. There normally small. And they are decomposers. Plus, Decomposers are necessary to keep nitrogen and carbon moving through the cycle, and not locked up in the atmosphere or in other organisms.

≅200-130 milions years ago pangea splited in 2 continents

within 30 of the equator hope this