In Earth atmosphere, which layer contains the ozone layer that absorbs most of the harmful ultraviolet (UV) radiation coming from the Sun?

Introduction / Context:
The atmosphere of Earth is divided into several layers, and each layer has its own special features and importance. One of the most important protective features is the ozone layer, which absorbs a large part of the Sun ultraviolet radiation. This question tests whether you know in which atmospheric layer this ozone shield is found.

Given Data / Assumptions:

• The atmosphere is divided into troposphere, stratosphere, mesosphere, thermosphere, and exosphere.
• The ozone layer is a region with relatively high concentration of ozone gas (O3).
• Ultraviolet radiation from the Sun can damage living tissues and cause skin cancer and other problems.
• The task is to identify which named layer contains most of this protective ozone.

Concept / Approach:
The troposphere is the lowest layer where weather occurs. Above it lies the stratosphere, which extends to around 50 kilometers above the surface. In the stratosphere there is a region with higher ozone concentration known as the ozone layer. This ozone absorbs a large portion of harmful ultraviolet B and ultraviolet C radiation from the Sun. The mesosphere lies above the stratosphere and is colder, while the ionosphere is a charged region overlapping upper layers and is important for radio communication, not mainly for ultraviolet protection. Therefore the correct answer must identify the stratosphere as the layer that contains the ozone shield.

Step-by-Step Solution:

Verification / Alternative check:
School geography and environmental science books clearly state that the ozone layer lies in the stratosphere. Diagrams of the vertical structure of the atmosphere show a peak in ozone concentration there. International agreements such as the Montreal Protocol aim to protect ozone in this stratospheric region, confirming that the stratosphere is the correct answer.

Why Other Options Are Wrong:

• Troposphere is wrong because it contains weather and most of the air mass but not the main ozone layer.
• Mesosphere is wrong because it lies above the ozone rich region and is not where the main ultraviolet shield is located.
• Ionosphere is wrong because it is defined by ionised particles and radio effects, not by high ozone concentration.

Common Pitfalls:
Students sometimes mix up troposphere and stratosphere or think that ozone must be in the lowest layer. A good memory trick is that weather lives in the troposphere, while the ozone shield lives in the stratosphere just above it. Keeping this order clear helps you answer many atmosphere related questions correctly.

Final Answer:
Stratosphere, which contains the protective ozone layer