What do humans release when they breath out

carbon dioxide

Explanation:

we inhale oxygen and exhale the carbon dioxide

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

d. planting trees

the trees take in carbon to make oxygen.