Question

what is the main function of the rough endoplasmic reticulum in a plant cell? to control which substances enter and leave the cell to help ribosomes make proteins to give strength and stiffness to the cell to break down sugar and release energy that the cell can use

Explanation:

The rough endoplasmic reticulum has ribosomes attached to its surface and is involved in protein synthesis. Controlling substances entering/leaving is the cell - membrane's role, giving strength is the cell - wall's function, and breaking down sugar is related to mitochondria.

Answer:

to help ribosomes make proteins