Post Utme Veritas University 2017 English Question 27

The following passage is from a book on environmental science. Read the passage and answer the question that follows. "The Amazon rainforest is the largest tropical rainforest in the world, covering an area of over 5.5 million square kilometers. It is home to an estimated 10% of all known plant and animal species, including thousands of birds, mammals, reptiles, and insects. The rainforest plays a crucial role in regulating the Earth's climate, producing about 20% of the world's oxygen, and absorbing carbon dioxide." What is the main purpose of the passage?