New generations are better suited to their environment than the first generation. what is this called?

Descent with modification

Explanation:

We define evolution as descent with modification from a common ancestor.

Evolution only occurs when there is a change in gene frequency within a population over time. These genetic differences are hereditary and can be passed on to the next generation - which is what really matters in evolution: long-term change. In this process, the new generations are better suited to their environment than the first generation because of descent with genetic modification.

substitution is the answer in this case

i was thinking 4.0 v hope this