Question 1: Which gas is the most abundant in Earth's atmosphere?

Answer: Nitrogen

Question 2: The process by which plants release oxygen into the atmosphere is called?

Answer: Photosynthesis

Question 3: True or False: Carbon dioxide is a greenhouse gas.

Answer: True

Question 4: True or False: The ozone layer is located in the troposphere.

Answer: False

Question 5: Explain why the Earth’s atmosphere is crucial for sustaining life.

Answer: The atmosphere provides essential gases like oxygen for respiration and carbon dioxide for photosynthesis. It also protects life from harmful solar radiation and helps regulate temperature.

Question 6: Describe the role of water vapor in the atmosphere.

Answer: Water vapor is a greenhouse gas that contributes to the warming of the atmosphere and plays a key role in the water cycle.

Question 7: What is the chemical formula for ozone, and in which layer of the atmosphere is it primarily found?

Answer: The chemical formula for ozone is O3, and it is primarily found in the stratosphere.

Question 8: Calculate the percentage of oxygen in the atmosphere using the formula: (Volume of O2/Total Volume of Air) * 100. Assume the volume of O2 is 21% of the total volume.

Answer: 21%

Question 9: Match the following atmospheric layers with their characteristics:

Answer: See full answer key

Question 10: Order the following steps in the water cycle:

Answer: See full answer key

Question 11: Fill in the blank: The layer of the atmosphere where weather occurs is called the _______.

Answer: troposphere

Question 12: Discuss the impact of human activities on the composition of Earth's atmosphere, including the effects on climate change. (6 marks)

Answer: Human activities such as burning fossil fuels, deforestation, and industrial processes increase greenhouse gas concentrations in the atmosphere, leading to global warming and climate change. These activities alter the natural balance of gases, contributing to the greenhouse effect, ozone depletion, and air pollution, all of which have significant environmental and health impacts.