This question is not clear, but I think I understand what you are asking. The difference between alleles of a gene is that some alleles may be dominant or recessive. If one gene has more dominant alleles than another, than it will be more visible.
Answer:
Krill
Explanation:
All animals in the Antarctic depend on krill, very small crustaceans, for their survival.
They are located in the liver the wall of the sinusoids.
MRNA is always single stranded
