What are fossils? What do they tell us about the process of evolution?

Fossils: Fossils are the remains or traces of a dead organism from the distant past. They tell about the changes and development that occurred on the earth’s surface and to the complex structured organisms from simple structured organisms.They exhibit the process of human evolution and states that angiosperms are developed from pteridophytes and gymnosperms and many more details which helps to understand the evolution and changes in environment.