An Introduction to Geography Test Yourself 1 The atmosphere is made up of a mixture of gases. Which of the following is a greenhouse gas? a) Oxygen b) Carbon dioxide c) Hydrogen d) Neon 2. Discuss advantages and disadvantages of dust particles in the air. 3. Describe the condition of life that would prevail on Earth if there is no water vapour in the atmosphere. 4. Nitrogen and oxygen are equally important for all the living beings on the Earth. Do you agree? Justify your answer.