Question

What are the main sources of air pollution in cities

• A. Humification - leads to the accumulation of a dark coloured humus which undergoes microbial action at a very fast rate.
• B. Leaching - water soluble inorganic nutrients leach to the upper layers of soil by percolation of water into soil particles.
• C. Catabolism - last step of decomposition carried out by saprophytic organisms.
• D. Fragmentation - Carried out by organisms such as earthworms.

Answer 1

The correct option is D Fragmentation - Carried out by organisms such as earthworms.

The main sources of pollution in cities are vehicles and industries.
In cities, air may be severely polluted not only by transportation but also by the burning of fossil fuels (oil and coal) in generating stations, factories, office buildings, and homes and by the incineration of garbage.