Question

which organelle is responsible for protein synthesis?
nucleus
ribosomes
cell membrane
endoplasmic reticulum

Explanation:

Ribosomes are the sites of protein synthesis in the cell. The nucleus contains genetic material, the cell - membrane is for protection and transport, and the endoplasmic reticulum is involved in protein and lipid synthesis but not the primary site for protein synthesis.

Answer:

B. Ribosomes