NEET BIOLOGY

Detailed explanation-1: -When UV-C light reaches the stratosphere, it is completely absorbed by oxygen molecules and never reaches the Earth’s surface. UV-C splits oxygen molecules into oxygen atoms. These single atoms then react with other oxygen molecules to produce ozone. So, these reactions increase the amount of ozone in the stratosphere.

Detailed explanation-2: -Ozone is formed when heat and sunlight cause chemical reactions between oxides of nitrogen (NOX ) and Volatile Organic Compounds (VOC), which are also known as Hydrocarbons. This reaction can occur both near the ground and high in the atmosphere.

Detailed explanation-3: -Oxygen is a byproduct of photosynthesis. About 70% of the oxygen in the atmosphere that we breathe comes from algae in the ocean. Atmospheric oxygen from photosynthesis also forms the ozone layer, which protects organisms from harmful high-energy ultraviolet (UV) radiation from the Sun.

Detailed explanation-4: -Through the photosynthetic process plants take up carbon dioxide and evolve oxygen. The present high concentration of molecular oxygen in the atmosphere is generally considered to have arisen from the activity of photo-synthetic organisms.

Detailed explanation-5: -At least half of Earth’s oxygen comes from the ocean. The surface layer of the ocean is teeming with photosynthetic plankton. Though they’re invisible to the naked eye, they produce more oxygen than the largest redwoods. Scientists estimate that 50-80% of the oxygen production on Earth comes from the ocean.