Water pollution

Water Pollution
D1.Name any two materials which can make rain water impure.
Ans:Dust and smoke are the  two  materials which pollute the rain water
D2.Name two human activities which can cause water pollution?
Ans: Washing clothes  and bathing in river or pond pollute the water.
D3.Which two pollutants are often dumped by factories into the river?
Ans: Harmful chemical and solid waste materials are dumped into the river by the factories.
D4.Name any two diseases that can be caused by drinking polluted water.
Ans: Two diseases that may causes by drinking polluted water are jaundice and cholera.
D5.Write the names of two types material, used by farmers to increase the production of crops.
Ans: Pesticides and chemical fertilizer are the two types of material used by farmer   to increase the crop production.
E1.How do wastes from factories and fields affect the aquatic animals?
Ans: Agricultural and industrial waste increase the number of micro-organisms in water ,which increase the BOD(Biological Oxygen Demand).Aquatic animal and plant do not get sufficient oxygen and finally die.
E2.How can polluted water affect the crops?
Ans: When polluted water is used in crop field it reduces the soil fertility which leads to low crop production.
E3.Why is oil spill harmful for marine life?
Ans: Oil spill from ships create a layer on the surface of water which cut –off the oxygen supply for marine life. Without oxygen marine life find difficult to survive. So oil spill is harmful for  marine life.
E4.State any four effects of water pollutions.
Ans:Effects of water pollutions are:
      1)Poisonous chemicals fromfactories kills marineanimals.
Human being suffer from many water borndiseasesby drinking polluted water.
Oil  spillscut-off the oxygen suply for marine animals and make their life difficult to survive.
Polluted water reduces the fertility of the soil.
E5.State four ways of reducing water pollution.
Ans:The ways of reducing  water pollutions are:
1.Do not  allowe  the factory waste directly intoriver.Treat the waste  ,reduces the toxicity and then release  the treatedwatertosomewhere.
2.people should not wash clothes or use soapsif  they bath in rivers.
3.the use of chemical fertiliser shouldbe minimised.
4.Water from drains or sewage should not be allowed to enter into wells or river.

Comments

Post a Comment

Popular posts from this blog

question bank

                                                            QUESTION BANK (TERM-2)                                                 STANDARD-IV    SUB-SCIENCE Q1) Fill in the blanks                                                  [1 mark each] a)       Our body makes vitamin-D in the presence of___________. b)       A bee-hive consists of many six-sided chambers called___________. c)        The silk moth weaves a cover around itself know as_____________. d)       Lac insects usually a grow on ____________trees. e)       Dengue is spread by the ____________ mosquitoes. f)        _______ gram of Fat gives about 18 kilocalories of energy. g)       We need vitamin _________ for good eye-sight. h)       Red colour pigment present in our blood is know as__________. i)         ____________is required for normal growth and development of the body. j)         A sting is located at the _________ of the insect. k)       Water which is clean and fit for drinking is c
Read more

class iv science birds beak and claws

BIRDS –BEAKS AND  CLAWS D1. Ans: Birds  use their beaks for preening their feather. D2.How is a crushing beak helpful to a pigeon? Ans:A crushing  beak is a short and hard beak.It helps the pigeon for crushing seeds and grains .so that the seeds will soft for eating. D3.What are claws? Ans: Claws are the long curved nails present on the feet of birds. D4.Name three birds of prey. Ans: Eagle, vulture and hawk are examples three birds of prey. D5.What prevents the body of  crane and jacana from sinking in water? Ans:The wide spreading toes of crane & jacana help them from sinking in water. E1.Write two main uses of a beak of a bird. Ans.Two main uses of beaks of a bird are: i)Beaks of birds are used for tearing, biting or  crushing the foods . ii)beaks of birds also help to fight the enemy or catch the prey. E2.How  claws helpful to a bird? Ans: Claws help a bird for climbing, protecting, holding food, swimming and perching. E3.How does a swallow c
Read more

Term --II Examination Practice Paper

D.A.V. PUBLIC SCHOOL, CHANDRASEKHARPUR, BHUBANESWAR Term –II Examination (2018-19) Practice Paper SUB:   SCIENCE TIME:2Hrs                               CLASS-IV           FULL MARKS:50 General Instructions: Ø This question paper contains three sections and 9 questions. Section ‘A’contains 1 mark questions   Section ‘B’contains 2 mark questions     Section ‘C’contains   3 mark questions and 4 mark questions. Ø Attempt all the questions. Ø Read the questions thoroughly. Ø Write in legible handwriting. Ø Verify the answers before submission of answer sheet. Ø Marks are indicated in right side. Section –A 1. Choose the most appropriate answer.                                                         (1×5=5)       i)It is not responsible for the shortage of water-    a) Rapid growth of industries b) Increase in population    c) Heavy rainfall      d) Mismanagement of water resources. ii) The insect, that helps in pollination is the-   
Read more