ПРОШУ ПОМОГИТЕ ОЧЕНЬ НАДО
С 5 ПО 10 ПРЕДЛОЖЕНИЯ

5 How are compounds produced?6 What isn’t changed in their characters in mixtures?7. How may oxygen and hydrogen be mixed?8. Why is oxygen the most important element to man?9. How much do oxygen,silicon,aluminium,hydrogen constitute of the Earth 's crust?10. Where have astronomers found common elements?