EVERYDAY SCIENCE

Detailed explanation-1: -Expert-Verified Answer. The group of organisms that survived mass extinctions that marked the ends of both the Paleozoic Era and the Mesozoic Era is the gastropods. Gastropods are one of the most diverse groups of animals, both in form, habitat, and habit.

Detailed explanation-2: -Alligators & Crocodiles: These sizeable reptiles survived–even though other large reptiles did not. Birds: Birds are the only dinosaurs to survive the mass extinction event 65 million years ago. Frogs & Salamanders: These seemingly delicate amphibians survived the extinction that wiped out larger animals.

Detailed explanation-3: -The Mesozoic closed with an extinction event that devastated many forms of life. In the oceans all the ammonites, reef-building rudist bivalves, and marine reptiles died off, as did 90 percent of the coccolithophores (single-celled plantlike plankton) and foraminifera (single-celled animal-like plankton).

Detailed explanation-4: -Both events were so significant they each marked the end of an era-the Mesozoic Era for the end-Cretaceous extinction and the Paleozoic Era for the end-Permian extinction.

Detailed explanation-5: -252 Million Years Ago: Permian-Triassic Extinction. 201 Million Years Ago: Triassic-Jurassic Extinction. 66 Million Years Ago: Cretaceous-Paleogene Extinction.