NCERT Class 4 Science Solutions the World of Microbes Part 2 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Match the following

Microbe and Charecterstics
List IList II
Blue green algaeBreak down dead plant and animals
FungiAn example of protozoa
PlasmodiumProduce antibodies
VaccinesNitrogen fixation
Saprophytic bacteriaA non-green plant

Select the correct word for the given images

Match Images and Microbes
Microbes and Images

Short Answer Question:

Q 1. Why is it so important to drink purified safe drinking water? Describe with example.


  • We should always drink safe drinking water as many harmful microorganisms live in water.
    • For example, protozoa live in water can cause diseases like amoebic dysentery and malaria.
    • Bacteria live in water can cause diseases like cholera and typhoid.

Q 2. How does vaccination work?


  • When a disease carrying microbe enters into our body, our body produces antibodies to fight the invader.
    • Therefore, intentionally weakened microbes are introduced in a healthy body so that the antibodies are produced and gain the capability to resist the disease further on.
    • This is how vaccination the works.

Q 3. Name some of the useful microorganisms. Describe how they are useful?


  • Many microorganisms are useful.
    • For example Fungi - The fungus yeast makes breads and idlies fluffy and spongy. Yeast helps in fermentation.
    • Some mushrooms are edible fungus.
    • Penicillin a lifesaving medicine is made from fungi.
  • Bacteria - Lactobacillus present in the curd promotes the formation of curd. Saprophytic bacteria break down dead plant and animals.
    • Bacteria Lactobacillus acidophilus helps in better digestion.