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Published on: 17/10/2019
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1.
Trees are very important for us.They balance carbon dioxide and oxygen in nature ,regulate rainfall,provide us fuel and shelter to many animals. But due to increasing population a lot of trees are used for industries,housing and transport purposes.So, the number of trees is fast decreasing.
Answer the following questions based on the above information :
(a) How can you help in increasing the numberof trees at school level?
(b) What can you do to spread awareness about importance and protection of trees?
(c) What value are displayed by their actions?
2.
Discuss the consequences of the increase in the concentration of carbon dioxide in the atmosphere.
3.
What is greenhouse effect? What will happen if concentration of greenhouse gases increases in the air?
4.
What is "greenhouse effect'? What would be its effect? name two greenhouses gases.
5.
List the organisms and their role in nitrogen cycle.
6.
Why is replenishment of forests necessary?
7.
How addition of undesirable substances and change in temperature affect the water the life?
8.
List three major factors which lead to water pollution. Give examples.
9.
What are the sources of water pollution?
10.
What is the role of the atmosphere in climate control?
11.
You know that the ozone layer of staratosphere of atmosphere protect us from ultraviolet radiations coming from the sun.Ozone layer is decreasing Scientist when talk about ozone 'hole' it means ozone layer at certain area has become very thin. Depletion of ozone layer is worldwide problem. Read more about ozone layer and its protection.
Answer the following questions based on the above information:
(a) On what three precautions/methods you will stress upon while organizing canpaign for creating awareness amongst masses?
(b) Which values are displayed by the students?
12.
Is it necessary to replenish forests?
1.
With the help of teachers we arrange 'A Van Mahotasav in our school' Each student will be asked to bring one sapling of any tree and plant it in the school or around the school premises.Also take care of it throughout the year.
(b) We will arrange campaigns for creating awareness amongst masses about planting and protecting trees.
(c) (1) Environmental protection
(2) Social responsibility
(3) Community service.
2.
The concentration of carbon dioxide in the atmosphere is increasing due to the current global trend of deforestation and increasing combustion of fossil fuels. A part of the sunlight incident on the earth reflected back in the form of infrared radiations. This infrared radiation are absorbed by the carbon dioxide molecules. hence, the envelope of CO2 of the atmospheric air would be able to trap larger proportion of the infrared radiations if the concentration of CO2 is increased, thereby heating the atmosphere.
This heating of the absorption of infrared earth's temperature and may cause melting of glacier and thereby flooding the coastal plains.
Greenhouse gases:
(i) CO 2 ,
(ii) Methane (CH4 ) and
(iii) Nitrogen oxide.
3.
The concentration of carbon dioxide in the atmosphere is increasing due to the current global trend of deforestation and increasing combustion of fossil fuels. A part of the sunlight incident on the earth reflected back in the form of infrared radiations. This infrared radiation are absorbed by the carbon dioxide molecules. hence, the envelope of CO2 of the atmospheric air would be able to trap larger proportion of the infrared radiations if the concentration of CO2 is increased, thereby heating the atmosphere.
This heating of the absorption of infrared earth's temperature and may cause melting of glacier and thereby flooding the coastal plains.
Greenhouse gases:
(i) CO 2 ,
(ii) Methane (CH4 ) and
(iii) Nitrogen oxide.
4.
The concentration of carbon dioxide in the atmosphere is increasing due to the current global trend of deforestation and increasing combustion of fossil fuels. A part of the sunlight incident on the earth reflected back in the form of infrared radiations. This infrared radiation are absorbed by the carbon dioxide molecules. hence, the envelope of CO2 of the atmospheric air would be able to trap larger proportion of the infrared radiations if the concentration of CO2 is increased, thereby heating the atmosphere.
This heating of the absorption of infrared earth's temperature and may cause melting of glacier and thereby flooding the coastal plains.
Greenhouse gases:
(i) CO2 ,
(ii) Methane (CH4 ) and
(iii) Nitrogen oxide.
5.
| Organism | Role/Activity |
|---|---|
| (i) Rhizobium and blue-green algae | Nitrogen fixation |
| (ii) Bacteria and Fungi | Ammonification (Organic Nitrogen \(\rightarrow\)Ammonia) |
| (iii) Nitrobactor and Nitrosomonas (Nitrifying bacteria) | Nitrification (Ammonia \(\rightarrow\) Nitrites) (Nitrites \(\rightarrow\) Nitrates) |
| (iv) Pseudomonas (Denitrifying bacteria) | Denitrification (Nitrates \(\rightarrow\) Free nitrogen) |
6.
It is very necessary to replenish forests for the following reasons:
(i) Rainfall: Trees give out enormous amount of water during transpiration. This water vapour helps in the formation of rain clouds. If trees are destroyed and not replenished the rainfall in the area will reduce. This may lead to less number of trees to grow.
(ii) Soil erosion: If trees are cut at a large rate the soil becomes barren. The top soil which is rich in organic matter will be washed away by water or carried away by wind. Thus reduction in rainfall and soil erosion may lead to the formation of desert.
(iii) Carbon dioxide-oxygen balance: Forests have very large number of trees. They give out \({ O }_{ 2 }\) and take in \({ CO }_{ 2 }\) in day time by the process of photosynthesis. Thus they help in maintaining carbon dioxide-oxygen balance in the atmosphere.
7.
A. Affect of addition of undesirable substances
(i) This may cause poisoning of water such as addition of mercury salt, lead, etc. cause the death of aquatic life such fishes.
(ii) Addition of estables, sewage, fertiliser, etc. cause growth of enormous algae and microbes that cause oxygen deficiency and death of aquatic life.
(iii) The polluted water may cause serious diseases in human beings, such as diahorrea, minamata (due to mercury salts) and many other diseases.
B. Change in temperature
(i) Affects the balance between various organism and may affect their breeding.
(ii) The eggs and larvae of various animals susceptible to temperature changes. For example, trout eggs fail to hatch at higher temperature.
8.
The term water pollution covers the following effects:
(i) The addition of undesirable substances to water bodies: For example, addition of industrial wastes containing poisonous salts like mercury salts, pesticides, insecticides, etc. Addition of disease causing organisms, like cholera causing bacteria through sewage.
(ii) The removal of desirable substances from water bodies: For example, depletion of dissolved oxygen and nutrients. This adversely affects aquatic animals and plants.
(iii) A change in temperature of water in water bodies: The aquatic animals are adapted to live under certain range of temperature. A sudden change of temperature may affect breeding of aquatic animals, their eggs and larvae etc. For example, pouring of water at very high temperature from nuclear reactors sometimes may cause death of fishes and aquatic animals.
9.
There are two types of sources of water pollution. These are:
(i) The sources which are located to close to water source and discharge pollutants directly into the particular water source. These may be factories, power plants, underground coal mines and oil wells situated near to water sources. It is possible to treat the pollutants before their release into the water body.
(ii) Some sources are scattered and do not have specific situation for discharging pollutants into a particular water body. These are run-off water from agricultural fields, gardens, lawns, roads, logging sites, construction sites etc. It is very difficult to monitor, regulate and treat non-point sources.
10.
The atmosphere prevents the sudden increase in temperature during the daylight hours. It slows down the escape of heat into outer space during the night. Thus, the atmosphere keeps the average temperature of the earth fairly steady.
11.
(a) (1) Before selling of old fridge or AC to junk purchaser remove the CPC compressure Take care that its gas does not leak in the atmosphere
(2) While purchasing new air conditioner or refrigeration,keep in mind it is ozone friendly i.e..it should contain HFC (Hydro-fluro carbon) instead of CFC
(3) Many mattresses and pillows are made of chemicals which harm ozone, Beware of them and purchase only ozone friendly products.
(4) While purchasing room refreshers,paint,etc., check that they do not contain CFCs
(b) By organising campaigns on the above said point for protection of ozone layer amongst masses they depict the following values:
(1) Relationship of common man and community with the ozone layer.
(2) Environmental protection.
12.
It is very necessary to replenish forests for the following reasons:
(i) Rainfall: Trees give out enormous amount of water during transpiration. This water vapour helps in the formation of rain clouds. If trees are destroyed and not replenished the rainfall in the area will reduce. This may lead to less number of trees to grow.
(ii) Soil erosion: If trees are cut at a large rate the soil becomes barren. The top soil which is rich in organic matter will be washed away by water or carried away by wind. Thus reduction in rainfall and soil erosion may lead to the formation of desert.
(iii) Carbon dioxide-oxygen balance: Forests have very large number of trees. They give out \({ O }_{ 2 }\) and take in \({ CO }_{ 2 }\) in day time by the process of photosynthesis. Thus they help in maintaining carbon dioxide-oxygen balance in the atmosphere.
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