1) Prehistoric life existed millions of years ago, long before written history. People lived in small groups, hunted animals, gathered plants, made stone tools and used fire. Many mysteries remain because scientists have only limited evidence, such as fossils, bones and cave paintings.
2) Dinosaurs were reptiles that lived on Earth for millions of years. They differed in size, shape, diet and way of life: some were huge, while others were small; some ate plants, and others ate meat. However, they were alike because they laid eggs, had scales and lived on land. Some probably moved in groups and cared for their young.