Scientists know how groups of animals changed over time by studying information contain in the?

Scientists know how groups of animals changed over time by studying information contained in the fossil record. The fossil record is a record of the remains of organisms that have been preserved in the Earth's crust over time. These remains can include bones, teeth, shells, and other body parts, as well as trace fossils such as footprints, burrows, and coprolites. By studying the fossil record, scientists can learn about the evolution of different groups of animals, including how they have changed over time, how they are related to each other, and how they have adapted to different environments.