Daily Olympiad: Science - Air [20260511]

Solution

Correct: A

The Ozone layer in the stratosphere (composed of O3 molecules) absorbs the majority of the sun's harmful ultraviolet (UV-B and UV-C) radiation, protecting living organisms from its damaging effects.

Solution

Correct: A

Carbon dioxide is the primary greenhouse gas produced through human activities like burning fossil fuels and deforestation. It traps heat in the atmosphere, contributing to global warming.

Solution

Correct: A

Chlorofluorocarbons (CFCs) release chlorine atoms when broken down by UV radiation, which react with ozone molecules, breaking them apart and thinning the ozone layer.

Solution

Correct: A

Renewable energy sources (solar/wind) reduce reliance on fossil fuels, while trees absorb CO2 and produce oxygen. Both practices reduce air pollutants.

Solution

Correct: A

Air is a homogeneous mixture (not a pure substance) of gases like nitrogen, oxygen, argon, CO2, and water vapor. The proportions of gases vary slightly depending on location and altitude.

Solution

Correct: A

A barometer is a scientific instrument used to measure air pressure, which is crucial for predicting weather changes and understanding atmospheric dynamics.

Solution

Correct: A

Oxygen is vital for both combustion reactions and cellular respiration in living organisms. It acts as the oxidizing agent in chemical reactions.

Solution

Correct: A

Uneven heating of Earth's surface creates temperature and pressure differences, causing air to move from high-pressure to low-pressure areas, resulting in wind.

Solution

Correct: D

Human activities like burning coal, oil, and natural gas for energy have significantly increased atmospheric CO2 levels beyond natural sources like respiration and decomposition.