Where in the atmosphere is ozone most beneficial to organisms on Earth?

• A. In the troposphere
• B. In the stratosphere
• C. In the mesosphere
• D. At ground level

Answer: (B)

Verified step by step guidance

1. Understand the role of ozone in the atmosphere: Ozone (O₃) is a molecule composed of three oxygen atoms. It plays a critical role in protecting organisms on Earth by absorbing harmful ultraviolet (UV) radiation from the sun.
2. Identify the layers of the atmosphere: The atmosphere is divided into several layers, including the troposphere (closest to Earth's surface), stratosphere (above the troposphere), mesosphere, and others. Each layer has distinct characteristics and functions.
3. Recognize where ozone is most concentrated: The stratosphere contains the ozone layer, which is a region with a high concentration of ozone molecules. This layer is located approximately 10 to 50 kilometers above Earth's surface.
4. Explain why the stratosphere is beneficial: The ozone layer in the stratosphere absorbs the majority of the sun's UV radiation, preventing it from reaching Earth's surface. This protection is essential for reducing risks such as skin cancer, cataracts, and damage to ecosystems.
5. Clarify why other layers are less beneficial: Ozone in the troposphere (ground level) can act as a pollutant, contributing to smog and respiratory issues. The mesosphere has very little ozone and does not play a significant role in UV protection.