Environmental Science

The mosquito life cycle includes the following stages in order:
1. Egg: Mosquitoes lay eggs on the surface of water.
2. Larva: The eggs hatch into larvae, which live in water and feed on microorganisms.
3. Pupa: Larvae develop into pupae, which are a transitional stage before becoming adults.
4. Adult: Pupae transform into adult mosquitoes, completing the life cycle.
Thus, the correct sequence is (B), (D), (C), (A).

The correct matches are:

• A. Cotton dust: Associated with Byssinosis, a respiratory condition caused by prolonged exposure to cotton dust.
• B. Asbestos: Causes Asbestosis, a chronic lung condition resulting from inhaling asbestos fibers.
• C. Silica: Leads to Silicosis, a lung disease caused by inhaling crystalline silica particles.
• D. Hay or grain dust: Results in Farmer's lung, a hypersensitivity pneumonitis caused by exposure to organic dust.

Thus, the correct sequence is: (A) - (I), (B) - (III), (C) - (II), (D) - (IV).

Occupational diseases are illnesses that arise due to exposure to risk factors or harmful conditions in the workplace environment. The following are occupational diseases:

• Silicosis: Caused by inhaling silica dust, commonly found in mining, quarrying, and construction industries.
• Byssinosis: Caused by inhaling cotton, flax, or hemp dust, often affecting workers in the textile industry.

Sickle cell anaemia and thalassemia are genetic disorders and not related to occupational exposures. Hence, the correct answer includes only (A) and (C).

Noise pollution is quantified using decibels (dB), which is a logarithmic unit that measures the intensity of sound. The threshold of hearing for humans is 0 dB, while levels above 85 dB are generally considered harmful to human health if exposure is prolonged.

Pneumoconiosis is a lung disease caused by inhaling dust particles, particularly in occupational settings such as mining, construction, or industries where workers are exposed to silica, asbestos, or coal dust. Prolonged exposure leads to scarring and impaired lung function.