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
D, is the answer. If you take antibiotics more than you're supposed to your immune system gets used to it and it no longer works.
There are pretty obvious differences between plants and animals, but at the chemical level the cells of all plants and all animals contain DNA in the same shape the famous “double helix” that looks like a twisted ladder.
It’s gravitational pull. The moon helped regulate the degree that Earth is tilted at, making the climate stable for life.