NCERT Class VII Science Solutions: Chapter 18-Wastewater Story Part 4

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Question 10:

Outline your role as an active citizen in relation to sanitation.

Answer:

Wastewater treatment plant requires costly infrastructure to build and to be maintained. So, we should be an active citizen and limit the type of waste. Try to follow the following:

  • Open drains be covered and keep our surroundings clean.

  • Should not litter anywhere adopt good sanitation practices e.g. oil and fats should not be thrown in drains.

  • Chemicals like paints, insecticides, motor oil etc. should not be thrown in drain which may kill useful bacteria.

  • Used tealeaves, solid food remains, soft toys, cotton, sanitary towels, etc. should also be thrown in the dustbin.

  • Make people aware and encourage community practices to keep our environment clean.

  • Separate trash as recycled waste and non-recycled.

Question 11:

Here is a crossword puzzle: Good luck!

As showing in images is a crossword puzzle

Crossword Puzzle (Q)

Across:

3. Liquid waste products

4. Solid waste extracted in sewage treatment

6. A word related to hygiene

8. Waste matter discharged from human body

Down:

1. Used water

2. A pipe carrying sewage

5. Micro-organisms which causes cholera

7. A chemical to disinfect water.

Answer:

As showing in images is a crossword puzzle

Crossword Puzzle (Solved)

Question 12:

Study the following statements about ozone:

  1. It is essential for breathing of living organisms.

  2. It is used to disinfect water.

  3. It absorbs ultraviolet rays.

  4. Its proportion in air is about 3%.

Which of these statements are correct?

  1. (a), (b) and (c)

  2. (b) and (c)

  3. (a) and (d)

  4. All four

Answer:

ii. (b) and (c)

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