Question

The theory of suggests that all the mammals alive today came from the same common ancestor.

Answer 1

Theory of Evolution

The theory of evolution has two points. One is that all the mammals alive today came from the same common ancestor and the other is that evolution takes place through natural selection.
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Answer 2

The theory of adaptive radiation suggests that all the mammals alive today came from the same common ancestor.

Step-by-step explanation:

Even though it might not sound something related to mammals, evolution, and biology. Adaptative radiation is the process in which one organism can evolution in a universe of different species when a major climate change occurs. Because this creates the perfect environment for species to adapt to a new life and develop the necessary characteristics to do it.