Why are proteins not usually used for energy?

Turning amino acids into molecules that can be used in the Krebs cycle takes energy, which means that burning protein for fuel is not as efficient as burning carbohydrates. In addition, your body needs amino acids to make new proteins.

Turning animos acids in molecules that can be used in the Krebs cycle takes energy which means that burning protein for fuel is not as efficient as burning carbohydrates

c is the correct answer hope this !

the answer to the blank provided is “an autosomal gene that is required for the expression of genes on the x chromosome”.

testis-determining factor, abbreviated as td, which is more popularly known as sex-determining region y or sry protein, is a dna-binding protein or  gene-regulatory protein/transcription factor, encoded by the  sry gene. it is the gene responsible for the initiation of male gender determination in humans.