Answer:

Dinosaurs are the animals that are no more and can only be seen in books and pictures. They lived millions of years ago during a time called the Mesozoic Era.

Explanation:

What are dinosaurs?
Dinosaurs were a group of reptiles that lived on Earth millions of years ago. They were a diverse group of animals that came in all shapes and sizes. Some dinosaurs were small, about the size of a chicken, while others were huge, like the long-necked Brachiosaurus.

Extinction of dinosaurs:
Dinosaurs became extinct about 65 million years ago. This event is known as the Cretaceous-Paleogene (K-Pg) extinction event. There are several theories about what caused the extinction of dinosaurs, but the most widely accepted one is the impact of a large asteroid or comet on Earth. This impact caused a massive explosion, leading to wildfires, tsunamis, and a cloud of dust and debris that blocked out the sun. Without sunlight, the Earth's climate changed drastically, leading to the extinction of many plant and animal species, including the dinosaurs.

Discovery and study of dinosaurs:
Dinosaurs were first discovered by scientists in the early 19th century. Since then, numerous fossils have been found all over the world, providing valuable information about these ancient creatures. Fossils are the preserved remains or traces of plants and animals that lived long ago. Paleontologists, scientists who study fossils, have been able to reconstruct the appearance, behavior, and habitat of dinosaurs based on these fossils.

Books and pictures:
Today, we can learn about dinosaurs through books, pictures, and other media. These resources provide detailed information about the different types of dinosaurs, their anatomy, diet, and the environments they lived in. They also help us understand the process of fossilization and the methods used by scientists to study dinosaurs.

Conclusion:
Although dinosaurs are no longer alive, their existence and importance in Earth's history can still be explored through books and pictures. These resources allow us to learn and appreciate the diversity of life that once roamed the Earth millions of years ago.