Question

which structure is present in both prokaryotes and eukaryotes?
plasmid
nucleus
endoplasmic reticulum
ribosome
cilia

Explanation:

Prokaryotes lack a true nucleus, endoplasmic reticulum, and cilia. Plasmids are mainly found in prokaryotes. Ribosomes are essential for protein - synthesis and are present in both prokaryotes and eukaryotes.

Answer:

Ribosome