Question

which of the following structures serves as the cells boundary from its environment?
mitochondrion
cell membrane
channel proteins
chloroplast

Explanation:

The cell membrane is a selectively - permeable barrier that separates the cell's interior from its external environment. Mitochondria are the power - houses of the cell for energy production. Channel proteins are embedded in the cell membrane for transport. Chloroplasts are for photosynthesis in plant cells.

Answer:

B. cell membrane