Answer: Option A. -> Deforestation→ loss of topsoil→ soil erosion→ no growth of plants→ desertification
:
A
Forest soil holds a lot of water, because of its porous nature and massive root system of trees. Falling leaves make up a good part of the dead organic matter on the forest topsoil serving as a reservoir of nutrients for plant growth. But when trees are cut, forests can no longer hold the soil together. In case of rains, the fertile soil would just flow along with water, leading to loss of the top soil. After some time this place is no longer fertile for other plants to grow. Ultimately it leads to desertification i.e., transformation of fertile land into a desert.

Answer: Option A. -> True
:
A
Around the year 1975, the Plantation Corporation of Keralastarted cashew plantations in Kasargod district. To prevent the tea mosquito bug from infecting the plantation, they used endosulfan asthe prime pesticide.

Answer: Option C. -> By forming a stable compound with haemoglobin
:
C
Carbon monoxide is produced by the burning of fuel in cars, trucks, fireplacesetc. It could accumulateindoors and couldpoison people and animals who inhaleit. Once carbon monoxide is inhaled, it enters the bloodstream and mixes with haemoglobin to form a stable compound, carboxyhaemoglobin. Whenthis happens, haemoglobin canno longer carry oxygen to the tissues. This lack of oxygen causes death of thecells and tissues.

Answer: Option B. -> Oil in a tanker
:
B
A pollutant when introduced into the environment, adversely affects the usefulness of a resource. A weed in the field, emission from cars, and chemical fertilisers sprayed on plants are all pollutants that affect the usefulness of the crops, pollute air and soil/water respectively. Oil in a tanker is not a pollutant by itself, but when it spills in water and affects marine life, it is called a pollutant.

Answer: Option D. -> All of these
:
D
Deforestation refers to the clearing of trees, transforming a forest into cleared land which directly leads to loss of wildlife habitat. Due to the loss of trees, the top fertile soil gets washed away during rains and it can also cause flood in highly deforested land. Deforestation plays several roles in flooding because trees prevent sediment runoff and forests hold the soil in place, reducing the movement of sediments that can shrink river channels downstream.

Answer: Option C. -> III - II - I
:
C
Biochemical Oxygen Demand is a measure of the quantity of oxygen used by microorganisms (e.g., aerobic bacteria) in the oxidation of organic matter. The higher the degree of pollution, greater would be the requirement of oxygen by microorganisms for decomposition. Therefore, highly polluted water has maximum BOD and distilled water has least BOD, as the latter does not contain microorganisms.

Answer: Option D. -> A - r, B - s, C - t, D - p
:
D
Combustion of fossil fuel causes the release of carbon dioxide.Wetland rice fields are identified as a major source of atmospheric methane. In a natural wetland and in paddy fields, flooding cuts off the oxygen supply from the atmosphere to the soil, which results in anaerobic fermentation of soil organic matter. Methane is a major end product of anaerobic fermentation. It is released from submerged soils to the atmosphere by diffusion and ebullition, through roots and stems of rice plants. Refrigeration requires a refrigerant, thatis a substance or mixture, usually a fluid, used in a heat pump andrefrigerationcycle. In most cycles it undergoes phase transitions from a liquid to a gas and back again. CFCs are used for this purpose. Burning of biomass primarily releases carbon dioxide, but it also releases another important greenhouse gas, nitrous oxide. Nitrous oxide is released only from the aforementioned process and hence, is matched to the burning of biomass.

Answer: Option C. -> Oil and grease
:
C
Solid waste is comprised of common items like paper, food and organic wastes, plastics, glass, metals, rubber, leather, textile, e-waste, hospital waste, etc.Liquid waste includes wastewater, fats, oils and grease (FOG), used oil, and hazardous household liquids.