Question

Identify the statement that is true about mass extinctions.A. Mass-extinction events are times in the Earth's history when few species evolve.B. The mass extinction of over two-thirds of the species on the Earth was the result of large volcanic eruptions in Hawaii.C. The mass extinction of dinosaurs occurred at the Permian-Triassic boundary.D. A mass extinction may happen when a comet or asteroid impact starts a chain of events that blocks sunlight for weeks or even years.

Answer 1

A. Mass-extinction events are times in the Earth's history when few species evolve.

Step-by-step explanation:

The extinction that occurred 65 million years ago wiped out some 50 percent of plants and animals. The event is so striking that it signals a major turning point in Earth's history, marking the end of the geologic period known as the Cretaceous and the beginning of the Tertiary period.

A wide range of animals and plants suddenly died out, from tiny marine organisms to large dinosaurs.

Species go extinct all the time. Scientists estimate that at least 99.9 percent of all species of plants and animals that ever lived are now extinct.