This is the correct option as all of these are the effects of air pollution on human beings. Hydrocarbon vapours damage the internal organs and cause cancer, suspended particulate matter causes asthma, bronchitis and allergic cold, and pollutant gases cause irritation in eyes, throat and lungs along with injuring lungs, liver, kidneys, spleen and nervous system.

This is the correct option as azotobacter plays the role of nitrogen fixation in nitrogen cycle.

This is the correct option as helminths are not chemical water pollutants. They are biological water pollutants.

This is the correct option as fertilisers, pesticides, petroleum oil and solid particles all are the causes of water pollution.

Pseudomonas converts nitrate salts into free nitrogen gas in nitrogen cycle. This process is known as denitrification.

This is the correct option as this is not a characteristic of non-renewable natural resources. Non-renewable natural resources are only abiotic in nature.

This is the correct option. Troposphere is the region of atmosphere which contains air and is the subject of differential heating.

This is the correct option as all of the above are the harmful effects of ozone depletion on human beings, animals, plants and environment. This is the correct option as all of the above are harmful effects of ozone depletion on human beings, animals, plants and environment.

This is the correct option. The amount of atmospheric ozone is expressed in Dobson units. The Dobson unit is the most common unit for measuring ozone concentration. One Dobson unit is the number of molecules of ozone that would be required to create a layer of pure ozone 0.01 millimeters thick at a temperature of 0 degrees Celsius and a pressure of 1 atmosphere.

This is the correct option. Living beings constitute the biotic component of the biosphere.

This is the correct option as this statement is false. In coastal areas, during night, there is a regular flow of cool air from the land towards the sea, and not from the sea towards the land.

This is the correct option. Wildlife is a renewable natural resource. Renewable resources are exhaustible resources which get replenished regularly. They can last forever if they are used responsibly.

This is the correct option as oil wells are a point source of water pollution. Being a point source, it is easier to treat the pollution coming out of oil wells before their discharge into nearby water bodies.

This is the correct option. Air contains about 78 % of nitrogen.

This is the correct option as all of the above are the causes of soil erosion.

This is the correct option. B-horizon is composed of mineral soil (subsoil). C-horizon contains the unconsolidated weathered rock fragments. D-horizon is composed of rock or unmodified parent material.

This is the correct option as this statement is false. The primary end products of chemical weathering, and not biological weathering, are silica, clay, inorganic salts and hydrated oxides.

This is the correct option. Cadmium was responsible for 'itai itai' disease in Japan. This disease was caused due to the eating of rice produced from soil containing high level of cadmium.

This is the correct option. Hydrogen has gaseous biogeochemical cycles. It is a cycle in which the reservoir is in the atmosphere or the hydrosphere. They are quick and relatively perfect systems, as their elements remain in more or less uniform circulation.

This is the correct option as nitrosomonas play the role of nitrification in the nitrogen cycle, i.e. convert ammonia into nitrites and then into nitrates.

This is the correct option as atmosphere forms the smallest global reservoir of water.

This is the correct option. Eutrophication is the process by which dissolved oxygen in water gets reduced due to excessive growth of algae as a result of extra loading of nutrients in the water body. This is a wrong option as the correct option is dissolved oxygen.

This is the correct option. Hydrosphere is the water on Earth's surface and sometimes includes water over the surface such as clouds. Troposphere is the lowest region of the atmosphere, extending from Earth's surface to a height of about 6–10 km. Thermosphere is the outermost layer of the atmosphere, between the mesosphere and interplanetary space, where air becomes extremely thin.

This is the correct option. Black soil is porous, contains humus and is rich in iron, calcium, aluminium and magnesium. Red soil is poor in lime, magnesium, phosphorus, nitrogen and contains very little quantity of humus. Laterite soil is rich in nutrients and is good for growing tea, coffee and coconut.

This is the correct option. The conversion of nitrate salts into free nitrogen gas is called denitrification.