Which of the following statements is true?
A: all the populations in an ecosystem form a community
B: a habitat represents all the biotic factors in an ecosystem
C: The amount of nutrients in soil is an example of a biotic factor
D: Only one population can live in a habitat at a time

A.  all the populations in an ecosystem forma community

Explanation:

b is the best answer for this question.

some fungi obtain their nutrients from a living host (plant or animal) and are called most biotrophic fungi have fairly narrow host ranges—they are specialized on a limited called rhizomorphs that allow the fungus to grow from one tree to another. ascospores are formed inside a sac-like structure called an ascus. so your answer is a