<span>C. Theyvare always multicellular </span>
We have 20 different amino acids in our bodies.
Answer: Definition
Explanation: In science, the word 'theory' refers to the way in which people interpret facts. A scientific theory is the framework for observations and facts. Theories may change, the way in which they are interpreted may change, but the facts remain the same.
A physician who specializes in treatment of the gums is called a periodontist.
