Air

Air

A1. Nitrogen & Oxygen 2. Oxygen 3. Carbondioxide 4.Photosynthesis 5.Ozone 6.Polluted air

B.1.True 2.True 3.False 4.False 5. True.

C.1.(b) Nitrogen   2,(c) smoke 3.(c) Water Vapour. 4.(d) Carbon dioxide 5.(b) Acid rain.

D1.Name  the main components of air.

Ans:The main components of air are nitrogen, oxygen, carbon dioxide &water vapour  .

D2.State  the meaning of the term photosynthesis.

Ans: Photo means light and synthesis means to combine. Photosynthesis is a process in which green plant prepare food  by combining water and carbon dioxide in presence  sunlight  and chlorophyll is called photosynthesis.

D3.State two possible harmful effects of ultraviolet  rays.

Ans: Two possible   harmful effects of Ultraviolet ray are:

i)Skin cancer in human being.

ii)Damage to the eye lenses of human being .

d4.Define  the term  Air Pollutants.

Ans:The Impurities present in air and are harmful to living organisms are called Air pollutants.

D5.Name any two of the gaseous pollutants presents in air.

Ans: Two gaseous pollutants present in air are carbon monoxide and sulphur dioxide.

D6.List any four causes of air pollution .

Ans: four causes of air pollution are:

1) Deforestation

2) Smoke emitted from vehicles

3) smoke from forest fire.

4) Smoke raised by burning of coal in power houses.

E1.Why is air necessary for animals?

Ans.  All animals including human beings need oxygen to live as it produces energy from the food eaten.  Air is important for every animal as it contains oxygen.

E2.How is nitrogen important   for plant?

Ans. Nitrogen is essential for the growth of plants. It helps them to develop their fruits and seeds. It also  increases the size and quality of the leaves.

E3.How is  the balance   of oxygen and carbon dioxide in air ,maintained in nature?

Ans: Plants need carbon dioxide for photosynthesis and produces oxygen where as animals need oxygen for respiration and produces carbon dioxide as a byproduct. The oxygen produces by plant use by animal and the carbon dioxide produced by animal used by plants. So the amount of oxygen and carbon dioxide is maintained in nature.

E4.Why is acid rain harmful?

Ans: Acid rain is harmful because it damages crops, damages monument and buildings, it increase acidity of the water and kills aquatic animals.

E5.why should we feel worried about global warming?

Ans: The extra increase in temperature of earth is called global warming. The increases in temperature leads to melting of  glacier and ice in polar caps, brings change in climate, increase floods ,desertification and so many devastation .So global warming is a worry for mankind.

E6.Suggest some ways of reducing air pollution.

Ans:Air pollution can be reduce by the following ways:

       I.            Promoting aforestation and decreasing deforestation.

     II.            Reducing uses of vehicles.

  III.            Using more cleaner fuels

  IV.            By regular check-up of vehicles

    V.            Constructing tall chimneys in industrials area.

  VI.            Dumping garbage in proper places

VII.            Adopting some good habits.

E7.How does planting of trees help in making air cleaner?

Ans: Plants absorb huge amount of carbon dioxide gas for photosynthesis. Plants act as greater natural carbon sink . If we will plant more tree more amount of carbon dioxide will be absorbed by plant .so air will be clean.