Answer and Explanation:
The Cretaceous–Paleogene extinction, which occurred around 66 million years ago, is defined as a mass extinction that wiped out around three-quarters of species on Earth.
Among the organisms that disappeared during this event, we find mammals, birds, fish, sharks, pterosaurs, birds, reptiles, insects, and some plant species.
This event is marked by the presence of a sediment layer known as the K-Ph boundary which showed important levels of iridium, an element that is abundant in craters. Therefore, after its discovery, scientists hypothesize this extinction occurred due to the impact of the giant Chicxulub crater which changed the conditions of the atmosphere.
