Biology

The correct answer is B.cell membrane.

The cell membrane (also called the plasma membrane) is most directly responsible for maintaining homeostasis in all cells. It regulates what enters and exits the cell, controlling the flow of nutrients, ions, water, and waste products. This selective permeability helps the cell maintain a stable internal environment, which is essential for proper function and survival.

Here's why the other options are not the primary structures for maintaining homeostasis:

A.Chloroplast: Found only in plant cells, chloroplasts are responsible for photosynthesis, converting light energy into chemical energy. While they play a vital role in ene...