Which of the following is a key function of Earth atmosphere that supports life on the planet?

Introduction / Context:
This general science and geography question tests your understanding of why the atmosphere is essential for life on Earth. The atmosphere is more than just the air we breathe; it performs several protective and regulating functions that make the planet habitable.

Given Data / Assumptions:

• The question asks about functions of the atmosphere that support life.
• The options mention supplying oxygen and water, screening ultraviolet radiation, and insulating the surface.
• It is assumed that you are familiar with basic roles of the atmosphere from school level geography or environmental science.

Concept / Approach:
The atmosphere is a mixture of gases surrounding Earth. Oxygen in the lower atmosphere is vital for respiration in most animals and many microorganisms. Water vapour in the atmosphere is part of the water cycle, allowing cloud formation and precipitation, which supply freshwater to land ecosystems. Ozone in the upper atmosphere absorbs a large portion of the Sun high energy ultraviolet radiation, reducing harmful exposure at the surface. The atmosphere also acts as a blanket, trapping some of the heat radiated from Earth surface through the natural greenhouse effect, which keeps surface temperatures within a range suitable for liquid water and living organisms. Together, these functions contribute to a stable environment where life can thrive.

Step-by-Step Solution:

Verification / Alternative check:
Textbooks in physical geography and earth science often list the major functions of the atmosphere in a dedicated section. Commonly mentioned roles include providing gases for respiration and photosynthesis, acting as a reservoir in the water cycle, protecting against meteorites and harmful radiation, and moderating surface temperature. Diagrams of the ozone layer and greenhouse effect further illustrate these protective and regulatory functions. Comparing these descriptions with the options confirms that each individual function is valid, so choosing all of the above is appropriate.

Why Other Options Are Wrong:

Supplies oxygen and water vapour needed for life processes alone is incomplete because it ignores the crucial protective and insulating roles of the atmosphere.

Screens out much of the Sun ultraviolet radiation alone is incomplete because it does not mention the importance of oxygen, water, and temperature regulation.

Insulates the surface against extreme temperature changes alone is incomplete because, without oxygen and water vapour, and without ultraviolet screening, life as we know it would still be in danger.

Common Pitfalls:
Some learners may choose the single function they remember best, such as oxygen supply, and overlook the others. Others might not realise how significant ultraviolet shielding and temperature regulation are for life. For example, without a moderating atmosphere, daytime temperatures could be extremely high and night time temperatures extremely low, as on some airless bodies in the solar system. The atmosphere works as an integrated system, providing gases, shielding radiation, and regulating heat, so it is vital to consider all these functions together.

Final Answer:
The correct response is that the atmosphere performs All of the above listed functions, all of which are crucial for supporting life on Earth.