GEOLOGY

Detailed explanation-1: -The fossil record shows us when specific types of organisms appeared, went extinct, or changed. And, the fossil record shows us that there have been mass extinctions in Earth’s past. A mass extinction is when many species die off around the same time.

Detailed explanation-2: -Fossils are the remains or traces of plants and animals that live a long time ago. Fossils help scientists understand what life was like millions of years ago. Some fossils provide evidence of living things that have gone extinct, which means they no longer found alive anywhere on earth today.

Detailed explanation-3: -Fossils found in a particular rock layer help scientists determine the age of the rock. Scientists use a technique called radiocarbon dating to find out the age of the fossils. Once they know the age of the fossil in the rock, they also know that rock itself is about the same age!

Detailed explanation-4: -Therefore, scientists are able to determine that most of the organisms on Earth are already extinct because they have noticed that they have features and characteristics that no longer exist in the living species.