The Life of Robots

Knowledge class
Before the birth of mankind, Other creatures have appeared on the earth,
Some of them still exist, and the vast majority are extinct,
including our well1-known dinosaurs.
A dinosaur is a reptile that once dominated the earth.
Some of them are vegetarian, some are carnivorous
Some are dull, and some are flexible;
Some crawl on land, some jump and run,some can fly.
The dinosaurs have appeared on the earth for 160 million years.
But it went extinct 65 million years ago.The cause of extinction is one of the
great mysteries in the history of life on earth.meteorite impact theory,
volcanic eruption theory,and climatic change theory etc.