Some of the questions the kids needed to answer while on their Earth Day hike.

1. What products except fuel are made of petroleum?

2. What are the colourless quarz crystals called?

3. What is the application of mined sands and construction gravels?

4. What are the 5 renewable sources of energy?

5. What does tidal energy consist in?

6. What is the source of heating and warm water in Island?

7. Why should we eat vegetable and animal proteins?

8. What is daily calcium nutritional requirement?

9. How many kilograms of potatoes and how many kilograms of apples contain the same amount of calcium as a glass of milk?

10. What are the 5 principles of healthy nutrition?

11. What are the water forms?

12. What are the water functions in a human's body?

13. What causes water circulation?

14. In which earth zones does water surface?

15. What human's actions may disturb ecological balance connected with water environment?

16. How does a pumped storage power station work?

17. Name the countries in which energy of waters is significant.