Consider the following state- ments : 1. Ozone is mostly found in the stratosphere. 2. Ozone layer lies 55-75 km above the surface of the Earth. 3. Ozone absorbs ultraviolet radiation from the Sun. 4. Ozone layer has no significance for life on the Earth. Which of the statements given above are correct ?

Ozone is primarily concentrated in the stratosphere, with approximately 90% of atmospheric ozone residing in this layer [3]. The ozone layer is typically found at an altitude of 15 to 35 km above the Earth's surface, not 55-75 km [4]. Statement 2 is therefore incorrect as the 55-75 km range falls within the mesosphere [2]. Ozone plays a vital role by absorbing harmful ultraviolet (UV) radiation from the Sun, specifically UV-B and UV-C rays [4]. This absorption is critical for life on Earth, as it acts as a protective shield against radiation that causes skin cancer, cataracts, and damage to plants and microbes [6]. Consequently, statement 4 is false because the ozone layer is essential for preserving life. Statements 1 and 3 are correct, making option 2 the right choice.

Sources

1. [2] FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 7: Composition and Structure of Atmosphere > STRUCTURE OF THE ATMOSPHERE > p. 65
2. [3] https://ozonewatch.gsfc.nasa.gov/facts/SH.html
3. [1] https://ozone.unep.org/ozone-and-you
4. [4] https://www.epa.gov/ozone-layer-protection/basic-ozone-layer-science
5. [5] https://education.nationalgeographic.org/resource/ozone-layer/
6. [6] https://www.un.org/en/climatechange/preserving-the-ozone-layer