Biology 3 Marks Question

Plastic containers, paper, electronic goods, left over food, food package, disposable glasses, cup plates, polythenes, excreta, soap and detergent waste are the wastes that one can generate at home, school or during trips to other places. Yes, we can easily reduce waste through judicious use of material by changing our habits & life styles.
Out of these, polythene and plastic material are hard to dispose off as they are non- biodegradable and they can be recycled back.

Eutrophication: It is excessive growth of algae, plants and animals in water bodies due to the nutrient enrichment particularly with nitrogen and phosphorus. It is both natural and accelerated. It leads to loss of bio-diversity and cuases chemical accumulation in food chain and ageing of water body.

Ground water depletion and replacement: Ground water depletion, a term often defined as long term water level declines caused by sustained ground water pumping, is a key issue associated with ground water use. Many areas of India experiencing ground water depletion.
The most servere consequence of excessive ground water pumping is that the water table, below which the ground is saturated - with water, can be lowered. If ground water level declines too far, then the well owner might have to deepen the well, drill a new well, or at least attempt to lower the pump.

1. Any discarded material that emits radiations is called radioactive waste. Radiations, emitted by nuclear waste is extremely damaging to biological organisms. It causes mutations to occur at a very high rate, resulting in various disorders like cancer. At high doses, nuclear radiation is lethal. The Defunct ships are dead ships that are no longer in use. Such ships are broken down for scrap metal in countries such as India and Pakistan. These ships are a source of various toxicants such as asbestos, lead, mercury etc. Thus, they contribute to solid wastes that are hazardous to health.
2. Defunct ships are dead ships that are no longer in use. Such ships are broken down for scrap metal in countries such as India and Pakistan. These ships are a source of various toxicants such as asbestos, lead, mercury etc. Thus, they contribute to solid wastes that are hazardous to health. E-wastes or electronic wastes generally include electronic goods such as computers etc. Such wastes are rich in metals such as copper, iron, silicon, gold etc. These metals are highly toxic and pose serious health hazards. People of developing countries are involved in the recycling process of these metals and therefore, get exposed to toxic substances present in these wastes.
3. Municipal wastes includes homes, offices, schools, hospitals etc. It is collected and disposed off by the municipality. These generally consists of paper, leather textile, rubber, glass, etc. Sanitary landfills are used to dump these wastes.

Women and communities have played a major role in environmental conservation movements.

• Case study of the bishnoi community: he Bishnoi community in Rajasthan strictly believes in the concept of living peacefully with nature. In 1731, the king of Jodbpur ordered his ministers to arrange wood for the construction of his new palace. For this purpose, the minister and the workers went to bishnoi village. There, a Bishnoi woman called Amrita Devi along with her daughter and hundreds of other Bishnois showed the courage to step forward and stop them from cutting trees. They embraced the trees and lost their lives at the hands of soldiers of the king. This resistance by the people of the village forced the king to give up the idea of cutting trees.
• Chipko movement: The Chipko movement was started in 1974 in the Garhwal region of the Himalayas. In this movement, the women from the village stopped the contractors from cutting forest trees by embracing them.

Biological magnification: Increase in concentration of persistent chemical at successive trophic levels is called eutrophication. This happens because a toxic substance accumulated by an organism can not be metabolized or excreted, and is thus passed onto next trophic level, e.g., DDT.

1. Natural ageing of lake is called as eutrophication. Its caused due to gradual accumulation of organic matter over a period of time.
2. Due to uncontrolled human activities like deposition of waste into the water bodies, there is an increase in the organic matter. Thus polluting the water.
3. The human activities accelerated the accumulation of organic matter, thus resulting is early aging of lake which is known as accelerated eutrophication.

1. What the villagers saw and are delighted about is algal bloom over a stationary water body. This algal bloom will cut off the supply of light and oxygen to the submerged flora and fauna of the water body. It will outcompete the water bodies flora and fauna for nutrients and will rapidly grow and deplete other organisms in the given water body ecosystem of necessary nutrients. This will quickly lead to the death, decay and destruction of the already existing water body ecosystem.
2. The flushed out and washed nutrients from the excess fertilisers of the nearby fields had accumulated and promoted the sudden burst in the growth of algal bloom on the water body. This phenomenon is often termed as Cultural or Accelerated Eutrophication.

Effects of sewage discharge on river are:

1. A sharp decline in dissolved oxygen and increase in BOD. Low oxygen levels in the water cause death of fish and other aquatic creatures.
2. Algal bloom which results from the presence of organic matter in water.

It causes:

1. Deterioration of the water quality.
2. Fish mortality.
3. Toxicity to humans and animals.

3. Biological magnification of a few toxic substances, as DDT causing harmful effects in living species.
4. Accelerated eutrophication, i.e. ageing of lakes and other water bodies due to human activities.

Rapid deforestation, massive burning of fossil fuel, have significantly increased the rate of release of carbon dioxide, polluting atmosphere, this green house gas, contributes to global warming.

Enrichment of water body by excessive nutrients is known as eutrophication.
The events of eutrophication are as follows:

High BOD of a water body indicates more number of micro-organisms in water, resulting in bad quality of water/death of aquatic creatures, more polluting potential.
Lower BOD of water body indicates less number of micro-organisms in water, good quality of water/aquatic life flourishes, less polluting potential.

1. A - algae/planktonic (free floating) algae.

B - fish/aquatic animals.

2. Due to excessive loading of nutrients/fertilizers from adjacent agriculture land resulting in increase in nutrients.
3. Decrease in dissolved oxygen (DO), increase in BOD, fish mortality, unpleasant odour/eutrophication.

An algal bloom is the phenomenon of excessive growth of planktonic forms in a nutrient rich water body. As the planktonic species multiply on the surface they form a layer that eventually covers the entire surface of the water body.
They block sunlight, which does not reached submerged aquatic plants that may have a role in supplying necessary nutrients to other aquatic life forms and keeping the water clean. Some algal species can release toxic substances.
Due to the high respiratory needs of such a huge concentration of biomass on the surface, the biological oxygen demand (BOD) of the water body increases, causing many of the life forms to die, their carcasses further contribute to the deterioration of the quality of the water content.

CNG/Compressed Natural Gas.
It burns more efficiently unlike diesel or petrol, very little of it is left unburnt, cannot be adultered, cheaper than petrol or diesel.

1. Particulate matter will pollute the air.
2. Use of CNG/Phasing out of old vehicles/Use of unleaded petrol/Use of low sulphur fuel/Use of catalytic converters/Application of stringent pollution level norms.

1. a = conformers.
2. Response of the regulators.
3. Maintain homoeostasis by physiological means, others either migrate or suspend activities.
4. Regulators.

1. Emission of greenhouse gases, absorb IR radiation from earth’s surface/emit it again to earth, the cycle continues, till the earth’s surface has no long wave radiations to emit.
2. Deleterious changes in the environment, odd climatic changes, melting of polar/Himalayan ice caps, rise in sea level, flooding/submerging of coastal areas.

Toxicants like DDT entered the trophic levels of the food chain, accumulated as it can neither be metabolised nor be excreted, toxicants disturb Ca metabolism, result in thinning of egg shells, premature breaking of eggs, population declined.

Use of CNG as the fuel, use of unleaded petrol, low-sulphur petrol/diesel, use of catalytic converter in the vehicles, phasing out of old vehicles.

1. Increase in level of greenhouse gases, molecules of these gases do not allow the infrared radiation of the earth to escape into space; this heat is radiated back, causing global warming.
2. Consequences - Polar ice caps and glaciers will melt, rise in sea level, mutation of DNA.

Biological magnification: The phenomenon through which certain pollutants get accumulated in tissues in increasing concentrations, along the food chain.DDT concentration increases in the phytoplankton relative to the concentration in water, zooplankton contained greater DDT than phytoplankton, in different fish the DDT concentration increased relative to the concentration in zooplankton, birds showed greater DDT concentration relative to that in fish.

Eutrophication: Process of nutrient enrichment of water, and consequent loss of species diversity.Consequences: Excess nutrients cause profuse growth of algae (algal bloom)/ blue-green algae causing oxygen deficiency in water.
Aquatic animals (e.g., fish) may die due to toxicity/ lack of oxygen.
Because photosynthesis which oxygenates the water ceases at night.

It. has electrode wires maintained at a very high voltage which produce a corona that releases electrons.

These electrons get attached to the dust particles and gives them a net negative charge. The collecting plates are grounded to attract the negatively charged dust particles' Thus, when the air passes through the collecting plate, it gets cleaned. Velocity of air between the-plares.is maintained at low value to allow the dust to fall on the collecting plate.

1. A: Planktonic algae, Decomposers

B: Fish, other aquatic animals.

2. Presence of large amount of nutrients like nitrogen and phosphorus.
3.  

• The growth of planktonic algae (algal bloom) causes deterioration of water quality and fish mortality.
• The decomposers acting on the dead plants and animals (organic matter) consume a lot of oxygen (increased BOD) and this causes mortality of fish and other aquatic animals.

1. BOD-Biochemical Oxygen Demand.
2. It indicates the addition of lot of organic matter; microorganisms 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.
3. When the amount of organic matter decreases and the microbes do not need oxygen for decomposition, the BOD decreases. Thus, aquatic organisms will start flourishing.

Multipurpose trees are that which are grown for more than one purpose or benefits. They may provide food in the form of fruit, seeds, or roots; and also provides firewood, medicines, fibres, etc.

1. Neem (Azadirachta indicd): Used as insect repellent, antibiotic, firewood and windbreaks.
2. Coconut palm (Cocos nucifera): Used for food, purified water (juice from inside the coconut), roof thatching, firewood, shade and rope making.

1. Yes, it is True.
2. Two applications of solar energy are; using solar cells to produce electricity, using solar cooker to cook food, using solar heater for hot water.
3. A cell which converts solar energy into electric energy is known as photovoltaic cell.

• BOD is the amount of oxygen required by the decomposer micro-organisms for decomposing the organic matter in the water.
• Higher the BOD, higher is the quantity of organic matter in the water body.
• If more organic matter is there, the microbes also flourish in the water body and increase their number.

1. It indicates that the sugar factory releases organic waste in the water body. To degrade the organic matter, microbes utilise the dissolved oxygen in the water, thereby, reducing the levels of dissolved oxygen and increasing the BOD.
2. In this part of river, the dissolved oxygen will be depleted making it difficult for aquatic species to survive. It can result in death of fishes in severe cases.

1. A-algae/ planktonic (free floating) algae.

2. Due to excessive loading of nutrients or fertilisers from adjacent agricultural land results increase in nutrients.
3. Effects: decrease in dissolved oxygen (DO), increase in BOD, fish mortality, unpleasant odour/ eutrophication.

S. No.	Biological Oxygen Demand (BOD)	Chemical Oxygen Demand (COD)
(i)	It is the amount of oxygen required for microbial breakdown of organic matter.	It is the amount of oxygen required for oxidation of both biodegradable and non-biodegradable organic matter in the water.
(ii)	Its value is less than COD.	Its value is more than BOD.

Higher biological oxygen demand shows that the dissolved oxygen in water bodies is much reduced and thus aquatic animals will die.

1. The management of non-biodegradable waste is of great concern as comparison to biodegradable waste because non biodegradable waste cannot be degraded by microbes and get accumulated in the environment. Biodegradable waste can be degraded by microbes into simpler form in which it can be used in ecosystem.
2. Two ways to organise 'zero garbage day' is as follows

1. Tell them about 'zero garbage day'.
2. Remind them rules to organise the day and also telling them importance of this day.

Trees and shrubs are effective in reducing noise level. Planting trees and shrubs near the boundary walls of buildings helps in reducing noise level and act as dust catchers. Such a line of trees along the boundary or along the roadside is also called sound barrier.

The word hybrid itself suggests the combination of two. Hybrid Vehicle technology is the technology which allows the vehicle to run on dual mode like petrol and CNG.Advantages of hybrid vehicle technology:

• As CNG is a green fuel, the fossil fuels are conserved.
• Reduction in environmental pollution.
• CNG is cheaper than petrol and diesel.
• CNG can’t be adulterated like petrol or diesel.

Six harmful effects of noise on human population are:

1. Sleeplessness.
2. Stress.
3. Increased rate of heartbeat and hypertension.
4. Breathing problems.
5. Damage of ear drums impairing hearing ability permanently.
6. Gastric problems-nausea.
7. Emotional disturbance

After green revolution, the use of inorganic fertilisers, etc., has increased to enhance the crop productivity. Pesticides, fungicides, herbicides are being increasingly used to serve this Purpose.
These chemical substances are toxic to non-target organisms and also pollute the soil and water bodies. They cause problems like eutrophication, biomagnification and soil pollution.

Snow-blindness is also known as photokeratitis. It happens because of exposure of eyes to UV-B radiation. Burning sensation, pain and increased tears are common symptoms of snow-blindness. The person suffering from snow-blindness feels that his eyes are full of sand.

1. With the rapid development of technology, as more and more electronic products are produced which is driving the ever-increasing production of e-wastes,
2. Following point can be explained to students to address the awareness issues.

1. Appropriate use of information technology equipment.
2. Safe disposal of e-waste.

3. Developed countries have exploited the developing countries with respect to e-waste managements. The information technology is more advanced in developed countries. They produce many equipment and export them to developing countries that leads to enormous collection of e-wastes in that countries.

1. The pattern A is depicted by microorganisms and pattern B is depicted by fishes or any other aquatic organism.
2. As the lake is adjacent to an agricultural land extensively supplied with fertilisers, the run-off water from the field will result in increase in nutrients of lake. Thus, number of microorganisms will rise to degrade organic matter.

Realising the significance of participation by local communities, the Government of India in 1980s has introduced the concept of Joint Forest Management (JFM) so as to work closely with “the local communities for protecting and managing forests. In return for their services to the forest, the communities get benefit of various forest products (e.g., fruits, gum, rubber, medicine, etc.), and thus the forest can be conserved in a sustainable manner.

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.