Question

Over the last billion years, many plant and animal species have evolved and then become extinct:

Options

• Only during periods of human activity

• At a roughly uniform pace

• Only within the last one million years

• Exclusively during asteroid impacts

Answer 1

Over the last billion years, many plant and animal species have evolved and then become extinct at a roughly uniform pace. This indicates that normal background extinction proceeds steadily, in contrast to the sudden losses seen in mass extinction events.