Question

What could happen if a person doesn’t get the proper amount of protein in his or her diet?

Answer 1

Protein deficiency can cause muscle cramping, weakness, and soreness. If you aren't consuming enough protein, your body will start to take protein from your skeletal muscles, which will lead to your muscles wasting over time.

Answer 2

Answer:

If a person doesn't get the proper amount of protein in his or her diet, the body would break down existing muscle to get the amino acids it needs.

You cannot just create protein and the amino acids out of nowhere, they are formed when you eat foods filled with protein. The consequences could be dire, as the body would be weakened to an extreme which is why the intake of protein is extremely important. 

(third  option)