Correct answer is Ribosome.
Ribosome is the cell structure where translation takes place. It is present in both eukaryotic and prokaryotic cells.
Translation is the process of making proteins from RNA, by creating a chain of amino acids linked together by polypeptide bonds. These proteins are needed for many cell functions. Ribosome is made from complex RNAs and proteins.
A ribosome is divided into 2 subunits – a larger subunit and a small subunit. Both subunits are composed of rRNA. Ribosomes can be found floating within the cytoplasm or attached to the endoplasmic reticulum.
Proteins made from free floating ribosome in the cytoplasm are used within the cell while proteins made by ribosome bound to a membrane are transported outside the cell.
The phrasing of the question makes the correct answer "ribosome" not "ribosomes" because of the singular verb used. To have the answer be "ribosomes," the question should read: "____________ are used in translation and are found on the endoplasmic reticulum.