In the atmosphere of the Earth, which layer primarily contains the ozone layer that shields living organisms from harmful ultraviolet radiation?

Introduction / Context:
The atmosphere of the Earth is divided into several layers, each with its own temperature pattern and importance. One of the most vital features in these layers is the ozone layer, which absorbs a large portion of harmful ultraviolet radiation from the Sun. Understanding where this ozone layer is located is a common general science question because it connects basic geography of the atmosphere with environmental protection and health.

Given Data / Assumptions:
We have to identify the atmospheric layer that mainly contains the ozone layer.
The options list four major layers of the atmosphere: troposphere, stratosphere, thermosphere, and mesosphere.
Standard textbook definitions of atmospheric layers are assumed.
The question focuses on the region where ozone concentration is highest, often called the ozone layer.

Concept / Approach:
The atmosphere is commonly divided into troposphere, stratosphere, mesosphere, thermosphere, and exosphere. The ozone layer is a region of comparatively high ozone concentration located mainly in the stratosphere, roughly between 15 and 35 kilometers above the Earth surface. This layer plays a crucial role in filtering out most of the Sun harmful ultraviolet B radiation, which can cause skin cancer, cataracts, and damage to plants and plankton. While small amounts of ozone exist in other layers, the bulk of the protective ozone layer lies in the stratosphere, so that is the correct answer.

Step-by-Step Solution:
Step 1: Recall the main layers of the atmosphere in order from the surface upward: troposphere, stratosphere, mesosphere, thermosphere, exosphere. Step 2: Remember that the ozone layer is located above the weather forming troposphere. Step 3: Identify that the ozone maximum is found in the lower to middle stratosphere. Step 4: Among the given options, select stratosphere as the layer that contains the ozone layer.

Verification / Alternative check:
Many diagrams in school textbooks show a band labeled ozone layer within the stratosphere. You may also recall environmental news about ozone holes forming over the polar regions at altitudes corresponding to the stratosphere. These sources consistently connect the ozone layer with the stratosphere, which serves as a quick verification of the answer.

Why Other Options Are Wrong:
The troposphere is the lowest layer where weather phenomena like clouds, rain, and storms occur, but it does not contain the main ozone layer.
The mesosphere lies above the stratosphere and is known for meteors burning up, not for the highest ozone concentration.
The thermosphere is much higher and is associated with phenomena like auroras and very thin air, not the ozone shield that protects life at the surface.

Common Pitfalls:
Students may confuse the troposphere and stratosphere because they are adjacent layers. Some think that because we experience weather in the troposphere, all important atmospheric features are found there. Others remember only the name ozone and guess randomly among the layers. Learning the order of layers and linking key features such as weather in the troposphere and ozone in the stratosphere helps avoid these errors.

Final Answer:
The ozone layer is found primarily in the Stratosphere.