Answer: b. The use of protein as an energy source is greater for endurance atheletes than those who body build or lift weights.
Explanation:
Proteins are the biomolecules. They are composed of polymers of amino acids. It is required by the body to repair tissues and build muscles, bones, and necessary component of skin, and cartilage.
The body of athletes require more protein than body builder or weight lifters. This is because during athletic practices like running, swimming and others the muscular mass should be strong enough to conduct long continous practice. The muscle mass is build up by proteins. The muscles may experience lack of oxygen during regular practice and may become weak. Thus require more protein so that the strength may remain maintained.
A codon is a sequence of three bases found on the messenger RNA (mRNA) molecule which is translated to produce an amino acid. Each amino acid is coded by one or more specific codons. If the codon is changed through a mutation, the amino acid produced may be different. However, in this case, the other codons that produce Leucine are:
UUA, UUG, CUU, CUC, CUA and CUG
So the code CUU could mutate to CUC, CUA or CUG and leucine would still be produced.