Question

select the part whose main job is to control which substances enter and leave the cell. cell membrane ribosome cytoplasm smooth endoplasmic reticulum

Explanation:

The cell membrane is a selectively - permeable barrier. It regulates the movement of substances in and out of the cell. Ribosomes are involved in protein synthesis. Cytoplasm is the jelly - like substance inside the cell where many cellular processes occur. The smooth endoplasmic reticulum is involved in lipid synthesis and detoxification.

Answer:

cell membrane