Question

Scientists found many different types of fossils in a rock layer, which was dated at 251–299 million years old using an index fossil. In layers directly above that point, scientists found a large decrease in the number of fossils, particularly of marine and insect fossils. When did the extinction event occur?

Answer 1

i think it is due maybe a lack of food for animals on land.

Step-by-step explanation:

It did not affect the water animals because they had food underwater. i don't know when it happened but just google your question.