NCERT Class 4 Science Solutions The World of Microbes Part 2

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Match the following

Microbe and Charecterstics
Microbe and charecterstics

List I

List II

Blue green algae

Break down dead plant and animals


An example of protozoa


Produce antibodies


Nitrogen fixation

Saprophytic bacteria

A non-green plant

Select the correct word for the given images

Match images and microbes

Match Images and Microbes

Match images and microbes

Microbes and images

Microbes and Images

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.

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