Which would be considered an ecosystem? A
a colony of bacteria
B
biotic factors in a forest
с
populations of zebras and lions
D
living and nonliving things in a pond

An ecosystem is a geographic area where plants, animals, and other organisms, as well as weather and landscape, work together to form a bubble of life. Ecosystems contain biotic or living, parts, as well as abiotic factors, or nonliving parts. Biotic factors include plants, animals, and other organisms

I hope this helps u

A colony of ants is a species,  C is only animals and only the biotic factors it is D living and nonliving things in a pond

Explanation:

layer 3 is younger than layer 6.