What gives scientists clues about the kind of organisms that lived in an ancient environment

Scientists make their opinion about the organisms that lived in an ancient environment based on multiple things. Fossils are very important because they show the organisms anatomy. The layers of the ground show the age and the basic climate information, as well as dramatic events in the Earth's history, like super volcano eruptions, meteor collisions, flooding's. Also the pollen is very important for knowing the environment, because it is everywhere and is preserved well, it gives clues about the climate, types of plants, the landscape, thus making opinion about the way of life of the organisms.