【单选题】Everything living on earth--plants and animals need other living things. Nothing lives alone. Most animals must live in a group, and even a tree or a plant grows close together with others of the same...
A.
Each plant can live alone.
B.
Each animal can live alone.
C.
Everything living on earth cannot live without needing other living things.
D.
If living things want to live they must kill each other.