Protein is when carbohydrates are scarce.
a. burned for energy
b. stored as glycogen
c. used to build muscles
d. stored as fat

The correct answer would be A. burned for energy.

When body cannot get enough energy from the carbohydrate and fats storage present in the body, it switches to the oxidation of protein for the production of energy.

Oxidation of proteins can provide 4 calories per gram.

The different amino acid can enter at different levels of cellular respiration. For example, alanine and cysteine are converted into pyruvate which then enters the cellular respiration et cetera.

it is a learned trait

explanation:

air enters through the nose, moves through the nasal cavity, the pharynx, the larynx, enters the trachea, moves through the bronchi andbronchioles till the alveoli.