What is this carpet made of?

Microvilli (1) and cilia (2) are seen on the same photomicrographs.

Do not mistake cilia (2) and microvilli (1): cilia possess 10 pairs of microtubules (a) (one central pair surrounded by the 9 others) that run throughout their length. Microvilli do not: inside the microvilli, you just see cytoplasm. Observe the plasma membrane (b) around the cilia.