Question

select the part whose main job is to make proteins. smooth endoplasmic reticulum chloroplast ribosome cytoskeleton

Explanation:

Ribosomes are the sites of protein - synthesis in the cell. The smooth endoplasmic reticulum is involved in lipid synthesis and detoxification, chloroplasts are for photosynthesis, and the cytoskeleton provides structural support and aids in cell movement.

Answer:

ribosome