Scientists found many different types of fossils in a rock layer, which was dated at 251–299 million years old using an index fo
ssil. 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?
A. The deaths of all plants and marine life in the area. It's because of the lack of oxygen since eutrophication often leads to algal bloom which in turn blocks the radiation and doesn't let oxygen to pass through it
