Read the text, then answer the questions below

We are destroying the the earth. The seas and rivers are too dirty to swim in. There is too much smoke in the air in many cities in the world. We are cutting down too many trees. We are burning the forests. We are also destroying lots of plants and animals. Many areas of the earth are wasteland. Farmers in many parts of the world can not grow enough to eat. In some countries, there is too lillte rice. The earth is in danger now. Save the Earth right now!

What is there in the air in many cities in the world?

• A. 
  too much water
• B. 
  too much smoke
• C. 
  many baloons
• D. 
  many trees