Answer:
Thermal Energy
Explanation:
I'll give you an example, Rub your hands together. Then touch your face or leg to feel any temperature change. Most likely your hands are warmer.
In nature there are many more variations amino acids than the simple 20 found in humans. However, when analyzing the human genome sequence, there is a code for all 64 permutations (4^3), only some of them share amino acids. This is a safe-guard against mutations of one or two nucleotides. For example, the amino acid Alanine is coded with four different nucleotide sequences: GCA, GCC, GCG, GCU. Also some amino acids code the same like UUU &UUC