Mitosis maintains complex organisms by which of the following processes? A) the removal of waste from the body
B) the exchange of gas with the environment
C) the formation of sperm and egg
D) the healing of a cut after an injury

In multicellular organisms, individual cells grow and then divide via a process called mitosis, thereby allowing the organism to grow. ... Cellular division and differentiation produce and maintain a complex organism, composed of systems of tissues and organs that work together to meet the needs of the whole organism.

Explanation:

d. planting trees

the trees take in carbon to make oxygen.