Birds, to read the diagram it’s easiest to look at which the lines intersect seeing how the birds and crocodile lines intersect closest to each other than any other animal does it shows that the correlation between birds and crocodiles are closer than the rest of the animals
I think the correct answer from the choices listed above is option B. Keratin is the protein in mammals which shows only a primary and secondary structure. Keratin is a fibrous protein forming the structural constituent of hair, feathers, hoofs, claws and many others.