Question

A(n) _____ includes all living and nonliving things in an environment.

Answer 1

Don't understand how this was particularly hard; I feel people are just lazy.

The answer is ecosystem.
This is because c refers to a single animal or species. (i.e. population of wolves in said ecosystem.)
Community would be specifically the animals living in an area.
And a landform is the natural feature of a solid surface.