What is the most fundamental unit of life according to the cell theory.

all LIVING organisms are made up of 1 or more cells. And cells came from other cells.

Explanation:

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