The ozone layer is essential for humans because?

Appeared in: NCL (MP) Nursing Officer - 2019

Explanation

The ozone layer is a protective shield located in the Earth's stratosphere.
Its primary and most critical function for human health is absorbing most of the sun's harmful ultraviolet (UV) radiation.
It specifically blocks the most damaging types of UV rays (UV-C and most of UV-B), which are known to cause skin cancer, cataracts, and immune suppression.
This filtering action is essential for making life on Earth's surface possible.

Option A: The primary source of breathable oxygen (O₂) in the atmosphere is photosynthesis by plants, algae, and cyanobacteria, not the ozone (O₃) layer.
Option C: While the ozone layer's absorption of UV rays does warm the stratosphere, it is the greenhouse effect, not the ozone layer, that is the primary mechanism for warming the Earth's surface to a habitable temperature.
Option D: This option is incorrect because a valid and correct statement is provided in the options (Option B).

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain The function and importance of the Earth's ozone layer as background academic context rather than a clinical decision trigger.
Understanding the ozone layer's protective role is fundamental to patient education on sun safety and preventing UV-related health problems.
Nurses must educate patients on the risks of excessive sun exposure, including skin cancer (melanoma, basal cell carcinoma), premature aging, and cataracts.
Key sun safety advice includes using broad-spectrum sunscreen (SPF 30 or higher), wearing protective clothing (hats, sunglasses), and seeking shade during peak UV hours (typically 10 a.m. to 4 p.m.).

How to Approach the Question

First, identify the core scientific concept being tested: the primary function of the ozone layer.
Read the question carefully: "The ozone layer is essential for humans because?". This asks for its main benefit to humanity.
Evaluate each option based on your knowledge of environmental science.
Analyze Option A: Is the ozone layer the source of our oxygen? No, that's photosynthesis.
Analyze Option B: Does the ozone layer block UV rays? Yes, this is its well-known primary function.
Analyze Option C: Does it increase Earth's temperature? It warms the stratosphere, but the greenhouse effect warms the surface. This is not its main essential role for life.

Concept Tested & Keywords

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E6 Medicine Harrison 22e Part 1 p. 470-472

E6 Comprehensive Textbook of Community Health NursingShyamala D part 1 (pp 26-389 of 389) p. 138-140

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Attempt every question from this paper in a timed mock, then review the full solution for each one.