Which of the following statements about Earth's atmosphere is FALSE?

• A. Water vapor is a variable component of the atmosphere and plays a role in weather and climate.
• B. Carbon dioxide makes up more than 50% of the Earth's atmosphere.
• C. The atmosphere is composed primarily of nitrogen and oxygen.
• D. The ozone layer in the atmosphere helps protect living organisms from harmful ultraviolet radiation.

Answer: (B)

Verified step by step guidance

1. Step 1: Begin by identifying the key components of Earth's atmosphere. Earth's atmosphere is primarily composed of nitrogen (approximately 78%) and oxygen (approximately 21%), with trace amounts of other gases such as argon, carbon dioxide, and water vapor.
2. Step 2: Evaluate the statement about carbon dioxide. Carbon dioxide makes up approximately 0.04% of Earth's atmosphere, which is far less than 50%. This statement is scientifically inaccurate.
3. Step 3: Analyze the role of water vapor in the atmosphere. Water vapor is indeed a variable component of the atmosphere, and it plays a significant role in weather patterns and climate regulation.
4. Step 4: Examine the function of the ozone layer. The ozone layer is located in the stratosphere and is crucial for absorbing harmful ultraviolet (UV) radiation, protecting living organisms from its damaging effects.
5. Step 5: Conclude by identifying the false statement. Based on the analysis, the false statement is: 'Carbon dioxide makes up more than 50% of the Earth's atmosphere.'