Choose the word or phrase (A, B, c or D)) that best fĩts the blank space in the following passage:

We are using up the world’s Petroleum. We use (6)_________in our cars and to heat our building in winter.Farmers use petrochemicals to (7)_________the soil rich. They use them to kill insects (8)_________eat plants. These Chemicals go (9)_________rivers and lakes and kill the fish there. Thousands of pollutants also go into the air and pollute it. Winds carry this (10)_________air to other countries and other continents.

Poor farmers use the samc land over and (11)_________. The land needs a rest so it will be better next year. However, the farmers must have food this year. Poor people cut down forests (12) _________ firewood. In some arcas when the trees are gone, the land (13)_________desert. Poor people canh save the environment for the (14)_________.

This is not a problem for one country or one area of the world. It is a problem for all- humans. The people and the nations of the world must work together to (15)_________the world’s resources.Question 13