Answer:
The tail of the sperm, the flagellum
Explanation:
We find cilia in the human body. They coat the epithelial cells of the upper respiratory tract and play a role in keeping dust particles, smog, and potentially harmful microorganisms from entering the lungs.
Their movements enable the movement of mucus or other substances across the surface of various epithelial cells. The cilia also cover parts of the male and female reproductive tract.
Flagella are found in sperm, whose tail represents the flagellum in its structure. The body wall of the sponge, among others, contains cells with whips that create and maintain the flow of water through the body.
Answer:
It requires ATP/energy
Explanation:
This is also known as active transportation. Moving from a lower concentration to a higher concentration will cost wayyy more energy than moving from higher concentration to lower concentration. You could think of it as a current, going against the current is harder!
Because if there's not a lot of a species it's likely to go extinct
The building blocks of proteins are amino acids, which are small organic molecules that consist of an alpha (central) carbon atom linked to an amino group, a carboxyl group, a hydrogen atom, and a variable component called a side chain