Here's why:

* Flagella are whip-like structures that help some cells move. They are primarily made of proteins, particularly flagellin.

* Ribosomes are the cellular machinery responsible for protein synthesis. They are found throughout the cytoplasm of a cell, including attached to the endoplasmic reticulum.

Where ribosomes are made: Ribosomes are assembled in a region of the cell called the nucleolus, which is located inside the nucleus. The nucleolus produces ribosomal RNA (rRNA), which combines with proteins to form ribosomes.