Internal means its on the inside
external means its on the outside
so an internal regulator is when the proteins respond to events on the inside of a cell
and an external regulator is when the proteins respond to events outside the cell
Same but like I got to answer questions before I can ask so sry
He observed 15 different finch species that originated as one ancestral bird. all differing in body shape, beak size, and mating habbits
Answer: B (Color blindness)
Explanation:
Typical red-green color blindness in human patients is caused by mutations on genes located in the X chromosome. These mutations act in a recessive manner. Since females have two X chromosomes, the presence of a mutation in a single one of them does not normally result in color blindness. Males, in contrast, have a single X chromosome and therefore the presence of a mutation is likely to cause the disease.
About the other options: Down‘s syndrome is a numerical chromosomal anomaly, not related to sex. Human blood type is a codominant trait. Finally, tail length in dogs is a polygenic trait not amenable to classic Mendelian analysis.