What I Know
Directions: Read each item carefully. Encircle the letter of the correct answer.

1. What refers to the envelope of air that surrounds the earth?
A. Atmosphere B. Biosphere
C. Hydrosphere D. Lithosphere

2. What is the most abundant gas in the earth's atmosphere?
A. Argon
B. Carbon dioxide
Nitrogen
D. Oxygen

3. In which layer of the earth's atmosphere do all weather phenomena take place?
A. Exosphere B. Mesosphere C. Stratosphere D. Troposphere

4. Which layer of the atmosphere contains the ozone layer?
A. Mesosphere B. Stratosphere C. Thermosphere D. Troposphere

5. The layer after the mesosphere where air is very thin is called the
A. Mesosphere B. Stratosphere C. Thermosphere D. Troposphere

6. What layer of the earth's atmosphere merges into space?
A. Exosphere B. Mesosphere
C. Stratosphere D. Troposphere

7. Which of the following gases are present in the atmosphere?
A. Water vapor B. Carbon dioxide and Ozone C. Oxygen and Nitrogen
D. All of these

8. In the troposphere, what happens to the temperature as altitude/height increases?
A. It decreases. B. It decreases then increases. C. It increases.
D. It remains the same.

9. What is the process where greenhouse gases trap the heat in the earth's atmosphere?
A. Global warming B. Greenhouse effect
C. Thermal expansion
D. Thermal heating​