Question

select the part whose main job is to control which substances enter and leave the cell. vacuole rough endoplasmic reticulum cell membrane chloroplast

Explanation:

The cell membrane is a selectively permeable barrier. It controls the movement of substances (such as ions, nutrients, and waste) into and out of the cell. This helps maintain the cell's internal environment. A vacuole stores substances like water and nutrients. The rough endoplasmic reticulum is involved in protein synthesis. Chloroplasts are for photosynthesis. So, the cell membrane is the correct answer as its main job is controlling substance entry and exit.

Answer:

cell membrane