The allele which has light color appears to be altering transcription and that is why the corresponding mRNA is absent in zebrafish which is homozygous. The protein we can say were absent because mRNA which is being required for protein synthesis it was not present.
If the allele had altered translation, mRNA which is functional would have been present but in the same case, the protein will still be absent.
Temperate Diciduous forest Biome
A dichotomous key helps you identify unknown specimens based on their traits because there are only two options available per trait. Selecting one from the two options (usually contrasting characteristics) from each step leads to smaller and smaller groups until the option is reduced to single and unique trait of an organism.
Considering you need to identify an organism. So, on the top of they key is animal with options: (a) with red blood cells and (b) no red blood cells. The option you will select is no red blood cells and under option b, you’re given two choices again: (a) hard bodies and (b) soft bodies. You’ll select soft bodies, then two options again are given: (a) with shell and (b) without shell. The option you’ll select would be without shell, and so on.
Adaptation would make the most sense