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A) Industrial and hospital waste

B) CO_{2 ,}NO_{2 ,} SO₂  gases in air 

Correct option is D) A and C

1. Clogging of drains

2. Inundation of areas 

3. Public health problems 

4. Pollution of drinking water sources 

5. Foul smell and release of gases 

6. Waste management problems

• The term pH is used to indicate the level of acidity or alkalinity of a soil. 
• The range of pH values of a good soil lies from 5.5 to 7.5. 
• Below pH 7 the soils are termed as acidic and above pH 7 alkaline. 
• The pH of soil is important in determining the type of vegetation that will grow in the soil. 
• Availability of plants nutrients is strongly tied to the pH in soil. 
• The availability of N, K, Ca, Mg and S tends to decrease with decreasing pH.

• Besides DDT the most important pesticides are Benzene hexachloride (BHC), chlorinate dihydro carbons, organophosphates, aldrin, malathion, dieldrin, furodan etc., are the examples.
• The remnants of such pesticides used on pests may get absorbed by the soil particles, which then contaminate root crops grown in that soil. 
• The consumption of such crops causes the pesticides remnants to enter human biological systems, affecting them adversely. 
• Pesticides not only have toxic effect on human and animals but also decrease the fertility of the soil. 
• Some of the pesticides are quite stable and their biodegradation may take weeks and even months.

1. Dangerous chemicals entering underground water. 

2. Ecological imbalance. 

3. Release of pollutant gases. 

4. Release of radioactive rays causing health problems. 

5. Increased salinity. 

6. Reduced vegetation.

1. The term pH is used to indicate the level of acidity or alkalinity of a soil. 

2. The range of pH values of a good soil live from 5.5 to 7.5. 

3. Below pH 7 the soils are termed as acidic and above pH 7 alkaline.

Negative impacts of low pH value :

1. The concentration of soluble metals especially aluminium and manganese may be toxic.

2. Calcium may be deficient. 

3. Soil organisms responsible to transform N, S and P to plant available forms may be reduced. 

4. Symbiotic nitrogen fixation in legume crops is greatly impaired. 

5. Soils will be having low organic matter. 

6. The availability of mineral elements to plants may be effected.

Negative impacts of high pH value :

1. If the pH is beyond 7, nutrient absorption and microbial activity will be affected which can be poisonous to plants. 

2. PH extremes are unhealthy for most plants because they close or open membranes of plant cells too much.

3. This affects plant structure and their ability to uptake nutrients. 

4. pH extremes make minerals and nutrients either too available or not available enough.

1. Colour texture, structure and porosity are the three main physical properties of soil.

2. These properties regulate and affect air and water movement in the soil and thus, soil ability to function.

• Soil with loose pores will allow water to collect and roots to expand. Loose soil is better than hard compact soil. 
• Finer particles like clay increase surface area of the soil which allow nutrients to stay in the soil.
• Very porous soil, such as sand will allow nutrients to be leached more easily which can make less nutrients available to plants. 
• Generally, a loose, airy soil structure is best for most plants. 
• This can be accomplished by digging the bed and mixing together coarse and finer textures such as tilling compost into clay soil.

Crop quality directly depends on the quality of the agricultural soil in which it is grown.

B) mercury, selenium

Topography: It ¡s the shape or configuration of the land represented on a map by contour lines.

Biosphere: All the life-supporting zones on earth are together called the biosphere.

Hydrosphere: Contains all of the earth‘s bodies of water.

Lithosphere: Solid rocky layer covering the entire surface of the planet.

Atmosphere: The gaseous envelope surrounding the earth constitutes the atmosphere.

Tillage: The process of preparing and using land for growing crops.

1. Crumb: A very small quantity of something.

2. Leaching: To be removed from soil by water passing through it.

3. Stench: A strong, very unpleasant smell. 

4. Trash: Things that we throw away because we no longer want or need them.

5. Smelt: To heat and melt ore.

6. Ooze: The liquid flows from the place slowly.

7. Clog: To block or become blocked. 

8. Inundate: To cover an area of land with a large amount of water.

Thawing: The process whereby heat changes something from a solid to a liquid.

Weathering: Breakdown of bigger rocks into smaller mineral particles.

Mycorrhiza: It is the symbiotic association that is taking place between a fungus and the roots of a plant.

Non-biodegradable waste: Substances that cannot be easily degraded.

Biodegradable waste: Substances that can be degraded by microbes into harmless and non-toxic substances.

Organic soil: Soil that contains 30% or more organic matter (residues of dead plants and animals) is considered organic soil.

Soil pollution: Soil pollution is defined as the build-up in soils of persistent toxic compounds, chemicals, salts, radioactive materials, or disease-causing agents, which have adverse effects on plant growth and animal health.

Soil is the most abundant and diverse ecosystem on the earth.

Correct option is D) Forests

B) contour ploughing

1. Contour ploughing 

2. Planting trees 

3. Crop Rotation 

4. Salinity Management

1. Reusing of materials 

2. Recycling and recovery of materials 

3. Reforesting 

4. Reducing chemical fertilizer and pesticides use.

1. Agricultural soil pollution 

2. Soil pollution by industrial effluents and solid wastes 

3. Pollution due to urban activities.

D) earthquakes, floods, land slides, hurricanes

B) Biological Oxygen Demand

A) Solid waste management involves collection, transfer and transport to suitable places.

D) Both A and B

B) 1 – c, 2 – b, 3 – a

Toxic chemicals leached from oozing storage drums into the soil, underneath homes, causing an unusually large number of birth defects, cancers and respiratory, nervous and kidney diseases.

The process of converting organic elements to inorganic forms and liberating CO^2, ammonia, sulphate, phosphate etc…. is called mineralization.

The soil type depends on 

a) Amounts of humus 

b) Size of the soil particles 

c) Microorganisms present in the soil.

• Soil erosion occurs when the weathered soil particles are dislodged and carried away by wind or water. 
• Deforestation, agricultural development, temperature extremes, precipitation including acid rain and human activities contribute to soil erosion. 
• Humans speed up this process by construction, mining, cutting of timber, over¬cropping and overgrazing. 
• It results in floods and cause soil erosion.

Correct option is B) 50000

Humus, living organisms and soil particles are present in the top soil.

Correct option is B) Loamy

D) All the above

B) Earthworms

B) Stratosphere

Fertile soil is rich in organisms that decompose dead organic matter into humus. Humus gives minerals, absorb water and makes soil porous.

Correct option is B) High pH