Answer:
A(the first one)
Explanation:
Homeostasis maintains the constant internal conditions in an organism. It is important because cells function best with a limited range of conditions. ... All living things have body parts with different functions that help them survive.
Plants can synthesize all twenty amino acids. Humans must eat plants or animals to obtain some of these amino acids. Proteins are broken down into pieces when human eat it. This helps in providing proper metabolism to the system.
Water, air, food, & shelter
