Skin color in a certain species of fish is inherited via a single gene with four different alleles. one fish of this type has alleles 1 and 3 (s1s3) and its mate has alleles 2 and 4 (s2s4). if each allele confers a unit of color darkness such that s1 has one unit, s2 has two units, and so on, then what proportion of their offspring would be expected to have five units of color?

50% Since each parent contributes 1 allele to their offspring, we can expect a even distribution of 4 allele combinations in the offspring of these fish. They are s1s2 = s1 from 1st parent, s2 from 2nd parent s1s4 = s1 from 1st parent, s4 from 2nd parent s3s2 = s3 from 1st parent, s2 from 2nd parent s3s4 = s3 from 1st parent, s4 from 2nd parent Since both the s1s4 and s3s2 offspring have 5 units of color, that would indicate that 50% of their offspring will have 5 units of color.

Probably a behavioral adaptation

Gases enter the atmosphere and trap the sun's heat warning the earth.