Ecologists study how relationships between biotic and abiotic factors impact the many levels of organization on earth. what level of organization is defined as groups of different species that live together in a single ecosystem? a) organisms b) ecosystems c) populations d) communities

D) Communities

Explanation:

Communities are groups of biotic living beings in an ecosystem such as animals, plants , bacteria, etc whereas populations are just groups of creatures of the same species. Multiple different populations make up a community.

a. decomposes use carbon from dead organisms as fuel for cellular respiration, returning carbon dioxide back into the atmosphere.