Question

what is the main function of the rough endoplasmic reticulum in an animal cell?
to make lipids
to break down waste and worn - out cell parts
to help ribosomes make proteins
to give structure and organization to the cell

Explanation:

The rough endoplasmic reticulum (RER) has ribosomes attached to its surface. Ribosomes are the sites of protein - synthesis. The RER helps in the synthesis, folding, and modification of proteins made by the ribosomes. Lipid synthesis occurs in the smooth endoplasmic reticulum. Waste and worn - out cell parts are broken down by lysosomes. The cytoskeleton gives structure and organization to the cell.

Answer:

to help ribosomes make proteins