Why are there only 64 codon combinations on the chart but only 20 amino acids

answerbacterium;

the right option is; decreased genetic variation  

decreased genetic variation describes the effect of this environmental change.

genetic variation is the naturally occurring genetic diversities or differences between organisms of the same species in a population. genetic variation allows the survival and adaptability of a species when they encounter changing environmental conditions. when an endangered species reduces, it loses genetic variation which may not be restored even if the species rebound and will only be recovered through the gradual collection of mutations over many years.

in the initial assessment of breathing, signs of respiratory distress must be noted (if present), such as the use of accessory muscles for breathing, abdominal breathing and grunting respiration. next, respiratory rate must be observed. increasing breathing rate may be a sign of sickness.