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.
While A is less direct in terms of homeostasis compared to D and E, it can be considered relevant to protecting the cell's internal environment. The other options (B and C) do not primarily pertain to the membrane's role in maintaining homeostasis.