Self-study activity:
Watch this short BBC clip and say whether the statements 1-7 are true or false.
1 Dinosaurs lived for about 150 million years.
2 Dinosaurs disappeared progressively.
3 To find out what happened to dinosaurs scientists began to investigate a layer of rock formed sixty-five million years ago.
4 What happened to dinosaurs is a total mystery today.
5 Big quantities of Iridium exist on earth.
6 When the dinosaurs disappeared, 10,000 iridium stones hit the earth.
7 Ten thousand asteroids must have hit the earth.
You can read the transcript here.
Key:
All the answers are false except question 3.