BIOLOGY 3 Marks Question

Noise on human health:

1. Sleeplessness.
2. Increased rate of heart beat.
3. Altered breathing pattern.
4. Stress.
5. Very high sound levels > 150 dB can cause damage to eardrum and permanent loss of hearing.
6. Chronic exposure to low level noise may also cause damage to hearing abilities.

• It refers to the increase in concentration of the harmful/toxic substances at successive trophic levels.
• It happens because such harmful/ toxic substances can neither be metabolised nor excreted, but are passed onto the next (higher) trophic level.
• In fish-eating birds, the high concentrations of DDT disturb the calcium metabolism.
• It causes thinning of eggshell and the premature breaking of such eggs leads to a decline in bird populations of fish-eating birds.

S.No.	Column I	S.No.	Column II
A.	Air (Prevention and control of Pollution) Act	iv.	1981
B.	Joint Forest Management water	iii.	1980
C.	Water (Prevention and Control Pollution)	i.	1974
D.	Environment (Protection) Act	ii.	1986

Accelerated eutrophication.

1. It primarily contains biodegradable organic matter degraded by the microorganisms. A mere 0.196 impurities make domestic sewage unfit for human use. The impurities include suspended solids (e.g. sand, silt and clay), colloidal material (e.g. faecal matter, bacteria, cloth and paper fibres), dissolved materials (e.g. nutrients like nitrate, ammonia, phosphate, sodium and calcium).
2. Clay and silt from soil erosion, leaching of minerals and filling of organic matter from the banks constitute natural sources of water pollution.

1. ​The benefits these trees impart to the farmland are:

1. Prevent soil erosion.
2. Provide shade during excessively high temperatures in the sunlight in hot season.
3. Regulate/ control wind speed.

2. Such trees are called multi-purpose trees.
3. Kishor is a vigilant, nature loving and attentive boy.

1. Burning reduces the volume of solid wastes.
2. Solid wastes are buried in the landfills.
3. Hospital wastes are incinerated.
4. Some materials are recycled.
5. Biodegradable wastes can be decomposed into manure.

1. Soil erosion is caused by over-cultivation, unrestricted grazing, poor irrigation practices and deforestation
2. Irrigation without proper drainage of water leads to waterlogging in the soil.

• Waterlogging draws salts to the surface of the soil which are deposited as a thin crust on the surface or collect at the roots of plants, this affects crop growth severely.

1. The three categories of wastes are:

1. Biodegradable.
2. Recyclable.
3. Non-biodegradable.

2. Since polysterene and plastic are non-biodegradable; they remain in the soil for several years and contribute heavily to environmental pollution.

• When DDT is sprayed on the crop plants, it remains in the soil as it is non-biodegradable and enters the plant.
• As it travels through food chain, it undergoes biomagnification, i.e. increase in concentration at successive higher trophic levels, as it can neither be metabolised nor excreted; this causes disorders in those organisms.
• In birds, a high concentration of DDT interferes with calcium metabolism and causes thinning of egg shells leading to their premature breaking, consequently there is a decline in bird population.

It is an established fact that conservation efforts in biodiversity rich area always give better results. Hills have better biodiversity than plans because of less degree of human intervention in plains. This is the reason the National Forest Commission of India has recommended a relatively larger forest cover for hills than for plains.

1. The gradual continuous increase in average temperature of surface of the earth, is called global warming.
2. Various causes of global warming are:
   1. High level of greenhouse gases in the atmosphere.
   2. Rise in atmospheric temperature.
3. Global warming can be reduced by taking following steps:

1. Cutting down use of fossil fuels.
2. Improving energy usage efficiency.
3. Reducing deforestation.

4. Planting trees and slowing down the growth of human population.
5. International initiatives are also being taken to curb the emission of greenhouse gases, mostly CFCS.
6. Kalpana is inquisitive, attentive and environment friendly.

1. Ozone is formed by the action of UV rays on molecular oxygen in the stratosphere.
2.  

• CFCs discharged in the lower part of the atmosphere move upward and reach stratosphere.
• In the stratosphere, UV rays act on CFCs and release Cl atoms.
• Cl atoms act as catalyst and degrade the ozone into molecular oxygen.
• Since Cl atoms are not consumed, whatever CFCs are added to the stratosphere, they have a permanent and continuing effect on ozone levels.

1. BOD

• Biochemical Oxygen Demand.

2.  

• It indicates the addition of lot of organic matter, micro-organisms involved in the biodegradation of organic matter in the water body consume a lot of oxygen and as a result, there is a sharp decline in the dissolved oxygen content downstream from the point of addition of effluent from the factory.
• This causes mortality of fish and other aquatic organisms.

Increase in the level of greenhouse gases in the atmosphere causes the rise in global mean temperature called global warming.Four strategies for reducing global warming are:

1. Reducing deforestation.
2. Planting trees (afforestation).
3. Slowing down the growth of human population.
4. Reduction of emission of greenhouse gases into the atmosphere.
5. Cutting down use of fossil fuels.
6. Improving efficiency of energy usage.

Scrubber:

• It is used to remove gases like sulphur dioxide from industrial exhaust.
• The exhaust is passed through a spray of water or lime.
• Water dissolves the gases and lime reacts with sulphur dioxide to form a precipitate of calcium sulphate or sulphite.

Algal bloom is caused due to large amounts of nutrients present in the waste water.

S. No.	Column I	S. No.	Column II
A.	0.04ppm	ii.	Zooplanktons
B.	2.0ppm	i.	Large fish
C.	0.5ppm	iv.	Small fish
D.	25ppm	iii.	Fish-eating birds

It causes deterioration of water quality and increased fish mortality rate. Some bloom forming algae are toxic to human beings and animals.

1. 'Swachh Bharat Abhiyan' is a cleanliness drive launched by Shri Narendra Modi, Prime Minister of India on 2 October 2014. I totally support this campaign. This initiative is needed to solve the sanitation problem and waste management in India. Following this drive all citizens will ensure hygiene across the country. It will spread awareness among people on the importance of clean surroundings. An unclean environment leads to various diseases, different types of pollution and creates a feeling of disgust in the minds of viewer. As a responsible Indian citizen, we all should join this drive with enthusiasm.
2. Two major problems can be:

1. Lack of adequate sanitation.
2. Separation of biodegradable and non-biodegradable substances, so that they can be treated properly.

3. Two remedial measures to overcome these problems are:

1. Large number of toilets need to be constructed and people should be made aware about the importance of proper sanitation.
2. Separate bins have to be installed for biodegradable and non-biodegradable substances.

1. Two dustbins of different colours are meant for separating the two types of wastes.
2. Two types of wastes are:

• Biodegradable wastes in the green dustbin).
• Non-biodegradable wastes (in the blue dustbin).

Biodegradable wastes	Non-biodegradable wastes
These are the wastes which can be broken down into simpler, harmless, (sometimes useful) substances by the action of living organisms through decomposition.	These are the wastes which cannot be broken down into simpler or harmless substances by the action of living organisms.

• Non-biodegradable wastes are more harmful, as they tend to remain as such for many years on the surface of earth; this type of wastes must be reduced significantly.

3. Non-biodegradable wastes must be reduced. Biodegradable wastes can be used for various purposes so as to reduce pressure on natural resources.

• Pollution from non-biodegradable wastes can be reduced.