BIOLOGY 2 Marks Questions

1.  

• A-Carbon dioxide
• C-Chlorofluorocarbons.

2.  

• Since these gases are responsible for the greenhouse effect, i.e. heating of the earth's surface, by absorbing the infrared radiation of the earth they are called greenhouse gases.

Cultural eutrophication is a form of water pollution. When eutrophication is accelerated due to human activities; it is called cultural eutrophication.
For example: Addition of excessive fertilisers into lakes results in cultural eutrophication.

Global warming can be controlled by:

1. Cutting down the use of fossil fuels.
2. Improving the efficiency of energy usage.
3. Planting trees and avoiding felling of trees.
4. Controlling the growth of population.

• As the exhaust passes through the catalytic converter, the unburnt hydrocarbons are converted into carbon dioxide and water, carbon monoxide and nitric oxide are converted into carbon dioxide and nitrogen gas.
• The metals include rhodium, platinum and palladium.

1.  

1. It is a fine powder of recycled modified plastic.

This mixture is mixed with bitumen used to lay roads:

Raw material: Plastic film waste.

2. Blends of polyblend and bitumen, when used to lay roads, enhances the bitumen's water repellent properties and helps to increase road life by a factor of three.

2. Irreparable computers and other electronic goods are known as e-wastes = 1

Burried in landfills or incinerated.

It is released. from petroleum. paper manufacturing, metal and chemical manufacturing industries into water bodies. The industrial effluents contain toxic heavy metals like mercury, cadmium, copper, Iead, etc.

1. The amount of garbage generated, especially in metros is so much that the landfills are getting filled very fast.
2. There is also danger of seepage of chemicals, which can pollute the underground water resources.

Vehicle running on dual mode like petrol and CNG are hybrid vehicle. As CNG is a green fuel there is conservation of fossil fuel and reduction in the environmental pollution.

Tetraethyllead is added to petrol or diesel to reduce knocking in engine. Knocking severely damages the engine. But lead in this compound poses several environmental and health hazards.

The plant growing near the boundary wall act as barrier for sound pollution and act as dust catchers.

It is a cyclic, zero waste procedure, where waste products from one process are cycled as nutrients for other processes. This allows the maximum utilisation of resource and increases the efficiency of production.

• It is a cyclical, zero-waste procedure, where waste products from one process are cycled in as nutrients/ resources for other processes.
• This allows the maximum utilisation of resources and increases the efficiency of production.
• Cattle excreta is used as manure as well as for generating biogas that can be used for lighting and cooking.
• Crop wastes are decomposed too and used as manure.

• Sulphur be controlled at 350ppm in diesel and 150ppm in the petrol.
• Aromatic hydrocarbons are to be contained at 42% of concerned fuel.

Electrostatic precipitators remove 99% of the particulate matter present in the exhaust of a thermal power plant.
In its absence, they will remain in the air as pollutants.

1. The human excreta can be recycled to form manure and thereby reduce the use of chemical fertilisers.
2. A large quantity of water can be saved.
3. It is a hygienic method of disposal of human excreta.
4. This method is efficient and cost-effective too.

As a result of global warming and climate change, regions such as Siberia will likely to become warmer and more habitable. The growing seasons in some regions will lengthen, as spring will arrive earlier and winter frosts set in later.

Pollutants which are formed by reaction between the primary pollutants in the presence of sunlight are called secondary pollutants.
Examples: Proxy-acyl nitrate (PAN) and Ozone.

1. A number of organisms will die that are sensitive to high temperature.
2. Hot water will reduce oxygen content of water and thus increased BOD will affect the aquatic animals.

Scrubbers are generally employed in removing gaseous pollutants. In a scrubber, the exhaust is passed through a spray of water or lime. Water dissolve gases and line reacts with sulphur dioxide to form a precipitate of calcium sulphate or sulphite.

• Irrigation without proper drainage causes waterlogging
• Waterlogging draws the salts to the surface of soil and the salts may get collecting on the roots.
• The increased concentration of salts is inimical to the growth of crop plants.

Yes, It is true that carpets and curtains/ drapes placed on the floor or wall surfaces can reduce noise level. These objects are made of fibres and fibres can absorb sound waves thus reduce noise level.

S. No.	Bad ozone	Good ozone
(i)	The ozone found in the lower atmosphere is called bad ozone.	The ozone found in the stratosphere is called good ozone.
(ii)	It harms both plants and animals.	It absorbs UV radiation and protects the living organisms from its harmful effects.

Yes, it is true, that placing/ using carpets on floor and curtains on wall surface, windows, reduces noise level. This is because the curtains on wall surface and carpet acts as muffling device and absorb sounds of moderate level.

Control of Noise Pollution:

1. Establishment of horn-free zones around schools and hospitals.
2. Use of acoustic materials in the wall of homes located in high sound zones.
3. Silencers must be fitted to automobiles and industrial gadgets.
4. Use of sound absorbent materials or mufflers in industries.

• The 'greenhouse effect' is a phenomenon that occurs in a greenhouse, where the glass panel lets the light in, but does not allow the heat to escape, consequently, the inside of the greenhouse warms up.
• Thus, the small glasshouse (greenhouse) is used for growing plants in winter, when it is very cold outside.

1. Conversion of forest to agricultural land.
2. Felling of tress for timber, firewood, etc.
3. Jhum Cultivation.
4. Clearing forests to make living areas.

1. In the absence of ozone which acts as a shield and absorbs the UV-rays, the UV rays reach the earth surface; UV rays are highly injurious to living organisms as it damages DNA and proteins.
2. In humans it causes:

1. Cataract, snowblindness and damage to cornea.
2. Damage to skin cells, aging of skin and skin cancers.

• E-wastes are recycled in the developing countries, as they recover some costly elements like copper, gold, nickel, silicon, etc.
• Recycling in developing countries involves manual participation and workers are exposed to the toxic substances and get certain respiratory diseases.

Air pollutants:

1. Cause breathing and respiratory disorders in humans and other animals.
2. Some air pollutants cause allergic responses.
3. Reduce the growth rate and yield of crop plants.
4. Cause premature death of plants.

Chipko movement was started in Garhwal, Himalayas in 1974 by Shri Sundar Lal Bahuguna to prevent cutting down of trees. The leaders of Chipko Movement believe in 5 Fs-food, fodder, fuel, fertilisers and fibres provided by the forest.

Limitation of using electrostatic precipitator is that it only works on gravitational settling method. Velocity of air between the plates is maintained low to allow the dust to fall in.

The smoke stacks of thermal power plants release particulate and gaseous air pollutants.These pollutants when inhaled deep into the lungs can cause:

1. Breathing or respiratory disorders.
2. Irritation, inflammations and damage to lung alveoli and
3. Premature death.

Control measure: By use of electrostatic precipitators, 99% of the particulate matter can be removed.

• The global warming is resulting in odd climatic changes and leading to melting of polar ice caps and other snow caps of mountains like Himalayas.
• Over many years, this will result in a rise in sea level, which can submerge the coastal areas.

• Algal bloom refers to the excessive growth of planktonic algae in water bodies.
• It is caused by the presence of large amounts of nitrates and phosphates in the water.
• Its harmful effects include:

1. Fish mortality and deterioration of water quality
2. Some bloom-forming algae are toxic to humans and other animals.

Particulate pollutants inhaled deep into the lungs cause irritation, inflammation, damage to the lungs, and premature death.

1. Chlorofluorocarbons.
2. In stratosphere, UV rays act on CFCs thereby releasing Cl, which degrades ozone, releasing molecular oxygen. Cl atoms act merely as catalyst and are not consumed in the reaction. A single chlorine atom can convert 1 lakh molecules of ozone into oxygen.