Question

where does protein synthesis occur?
nucleus
mitochondria
cytoplasm
ribosome

Explanation:

Protein synthesis occurs at ribosomes. Ribosomes are the cellular structures responsible for translating mRNA into proteins. The nucleus contains genetic material but doesn't synthesize proteins. Mitochondria are for energy production (ATP). Cytoplasm is the medium, but ribosomes (in cytoplasm or on ER) do the synthesis.

Answer:

Ribosome