1. Find equivalents:

2. Complete the sentences:

1. The Universe contains everything that exists – not only the Earth and everything on it, but also

2. The center of the solar system is

3. Most scientists think that the universe was formed

4. Our solar system is made up of

5. The heaviest of all the planets is

6. Stars are

7. The energy generated by the process in a star’s core called fusion produce

8. Each galaxy contains

9. The only planet known to support life is

10. Air is

11. The layer of air that we breathe stretches

12. The key elements of air are

13. Some of our activities threaten the world's habitats and therefore

14. The balance of nature is upset by

15. Lots of different populations share the same

16. Ecology is the study of

3. Answer the questions:

1. How many stars are there in our galaxy?

2. What is the Milky Way?

3. How many and what are the planets in our solar system?

4. What holds the planets together?

5. What chemical elements take part in the process of nuclear fusion at a star’s core?

6. What planet is the third nearest the sun?

7. When was the Earth formed?

8. What metals collected at the centre of the Earth while its forming?

9. Why is air necessary for people?

10. What is referred to humidity?

11. Who have the greatest effect on the environment?

12. What is biodiversity?

13. What damage to the environment do people produce?

14. What is considered the main cause of over-activity of people?

15. What does the biosphere consist of?

16. What do lots of different populations sharing the same habitat form?

17. What do the relationships between the members of the community include?

4. Translate the text «Y. Gagarin» (Additional Reading) and find some information about a famous contemporary Russian astronaut.

5. Translate the text «Space Tourism» (Additional Reading). Discuss this topic with your partner.