Answer:
A. The mass extinction of dinosaurs occurred at the Cretaceous/Paleogene boundary.
Explanation:
The most known extinction is the associated with the Dinosaurs, which happened at the Cretaceous/Palogene boundary (66 million years ago), although there is still a huge discussion on the causes of such extinction (comet/asteroid, changes in sea level, volcano activity).
Such event meant the dissappearing of two-thirds of the living species on Earth.
Answer:
D
Explanation:
Mass extinction is defined as an occurrence that cause a rapid extinction of a large number of species across the earth within a short period of time.
Factors that causes mass extinction are change in climatic condition ,massive volcanic eruption ,and effects of asteroids.
When asteroid impact can ignite a chain of worldwide volcanic eruption which effect can lead to a mass extinction of different species of animal.
