8.

Mass extinctions occurred 250 million years ago and 65 million years ago. According to some scientists, which of the following reasons caused both mass extinctions?

A new species was introduced into an established ecosystem.

The diversity in the gene pool decreased dramatically.

A large comet or asteroid hit the Earth.

The Earth’s oceans changed a few degrees in temperature.

1 answer

C. A large comet or asteroid hit the Earth.