Question

select the part whose main job is to produce steroid hormones. rough endoplasmic reticulum smooth endoplasmic reticulum cytoskeleton ribosome

Explanation:

The smooth endoplasmic reticulum (SER) is involved in lipid synthesis. Steroid hormones are lipids. So, the smooth endoplasmic reticulum is responsible for producing steroid hormones. Rough endoplasmic reticulum is for protein synthesis (with ribosomes attached). Cytoskeleton provides structural support. Ribosomes are for protein synthesis.

Answer:

smooth endoplasmic reticulum