Final answer:
Ribosomes are present in both prokaryotic and eukaryotic cells, serving as the site of protein synthesis. In prokaryotic cells, they float freely in the cytoplasm, essential for protein production.
Step-by-step explanation:
The component that is present in a prokaryotic cell is B) ribosome.
Prokaryotic cells, unlike eukaryotic cells, do not have membrane-bound organelles such as mitochondria, chloroplasts, and endoplasmic reticulum (ER). However, ribosomes are a crucial element found in both prokaryotic and eukaryotic cells. These are the sites of protein synthesis and are essential for the cell's production of proteins. In prokaryotic cells, ribosomes float freely within the cytoplasm, whereas in eukaryotic cells, they can be either free in the cytoplasm or attached to the rough endoplasmic reticulum, facilitating protein synthesis. The ribosomes found in mitochondria and chloroplasts of eukaryotic cells resemble those in prokaryotic cells more than they do the nuclear ribosomes in the same cell, reflecting their evolutionary origin from endosymbiotic bacteria.