Question

Based on the timeline, about how many years ago could the oldest mammalian organism have lived?

5 million years

200 million years

1.5 billion years

4.5 billion years

Answer 1

200 millons years.
Hope this helps!

Answer 2

The correct answer is option B, 200 million years ago

The mammals first evolved some 200 million years ago as dinosaurs on the planet Earth. This can be estimated through radiometric dating. There was transition from reptiles to mammal which led to the emergence of mammal like reptiles known as stem mammal or proto mammals. The mammals have basically evolved from the group of reptiles knows as Synapsids