The fossil record indicates that in some cases reasonably well-defined species appear suddenly and remain unchanged for a long time before they become extinct. This phenomenon is referred to as

Answer :

Answer:

The correct answer is - punctuated equilibrium.

Explanation:

The phenomena represent punctuated equilibrium, according to which the new well-defined species appear suddenly and quickly. These species remain unchanged for a long time as they occur because of mutations in genes.

This phenomenon suggests that once it made in the fossil record the population becomes stable for a long time until they become extinct and have to adapt to the changes take place to survive.