By elimination: d is wrong for sure.
c is not right as there is no gland in the esophagus or the pharynx
b is also wrong as if there is no gland, then there is no enzyme and no chemical digestion in <span>esophagus or pharynx
a is the only one left.</span>
Answer:
adaptive radiation
Explanation:
In biology, adaptive radiation is the process where organisms quickly diversify from an ancestor species into a multitude of new forms, especially when a change in the environment makes new resources available, alters interactions or opens new environmental niches.
To be honest, since we live on Earth (assuming you do as well), Earth is the easiest planet to study. We don't know much about the other planets because we've never been to any of them. I believe that the second easiest planet to study is either Uranus or Saturn.