The three ways that the cell membrane helps maintain homeostasis within a cell are:
D. The cell membrane controls the concentration of organic molecules in a cell's cytoplasm.
E. The cell membrane allows water into and out of the cell.
A. The cell membrane protects all of the organelles within the cell from injury.
(Note: While option A is more related to protection rather than homeostasis, the most directly relevant options for homeostasis are D and E.)