Multiple choice

In which era did the first mammals appear on the earth?

  1. Permian-Paleozoic

  2. Triassic-Mesozoic

  3. Tertiary-Coenozoic

  4. None of the above

  5. -

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The first mammals evolved toward the end of the Triassic period of the Mesozoic era.