Introduction / Context:
Understanding the structure of the air envelope around the Earth is a basic part of geography and general science. The Earth is surrounded by a mixture of gases that support life, regulate temperature and protect us from harmful radiation. General knowledge questions often test whether students can distinguish between the overall layer of air and its various sub-layers such as the troposphere, stratosphere or ionosphere.
Given Data / Assumptions:
• The question asks for the name of the entire layer of air around the Earth.
• Options include troposphere, ionosphere, atmosphere and ozone layer.
• We must pick the broad, all-encompassing term.
Concept / Approach:
The total blanket of gases surrounding the Earth is called the atmosphere. It is divided into different layers based on temperature and composition, such as the troposphere (lowest layer), stratosphere, mesosphere, thermosphere and exosphere. The ionosphere is a part of the upper atmosphere rich in ions, and the ozone layer is a region within the stratosphere where ozone concentration is relatively high. Therefore, only ‘‘Atmosphere’’ refers to the entire layer of air around the planet.
Step-by-Step Solution:
1. Recall that the Earth is surrounded by air composed of nitrogen, oxygen, carbon dioxide and other gases.
2. The collective name for this gaseous envelope is ‘‘atmosphere’’.
3. Troposphere is just the lowest part of the atmosphere where weather occurs.
4. Ionosphere is a high region with ionised particles, not the whole air envelope.
5. The ozone layer is confined mainly within the stratosphere and is not the entire atmosphere.
6. Thus, the only option that covers all layers together is ‘‘Atmosphere’’.
Verification / Alternative check:
Standard geography and science textbooks describe the atmosphere as the gaseous envelope of the Earth, extending from the surface to hundreds of kilometres in height. Diagrams clearly label troposphere, stratosphere, mesosphere and other layers as parts of the atmosphere. This confirms that ‘‘atmosphere’’ is the correct overarching term for the entire air layer around our planet.
Why Other Options Are Wrong:
Option A, troposphere, refers only to the lowest layer, typically up to about 8–18 kilometres depending on latitude. Option B, ionosphere, covers a region where ionisation is significant, mainly in the upper atmosphere, but does not include the lower layers. Option D, ozone layer, is a specific zone of high ozone concentration within the stratosphere, not the full air envelope. Therefore, these terms are too narrow for the question asked.
Common Pitfalls:
Students sometimes confuse the names of layers and mistakenly think that troposphere or ozone layer describes the whole air cover. Another pitfall is to associate ‘‘atmosphere’’ only with weather, whereas it actually includes all gaseous layers. A clear memory cue is that ‘‘atmo’’ means air and ‘‘sphere’’ means layer or region, so atmosphere literally means the air-layer surrounding Earth as a whole.
Final Answer:
The layer of air surrounding the Earth is called the
atmosphere.
Discussion & Comments