NCERT Solutions Curiosity Chapter 2 Activity 2.7: Let us do — Key players in cleaning the environment
Book page 18 Updated on2026-09-05
Q1.
After 2–3 weeks, observe the changes that have taken place. Do you observe any difference in the contents of the container?
Answer
Yes. The fruit and vegetable peels are no longer recognisable — they have turned into a dark-coloured material.
What you will notice after 2–3 weeks:
The peels have lost their original colour and shape and become a dark, crumbly material.
The total volume of the contents has gone down.
The material smells earthy rather than of rotting fruit.
This dark material is manure. It is rich in nutrients and helps increase the fertility of the soil.
Tip: keep the container in a shaded place and let it stay slightly moist but not waterlogged. The book states that manure formation occurs at optimal temperature and appropriate moisture level — too dry and the process stops, too wet and air cannot get in.
Q2.
But how did the peels of fruits and vegetables turn into manure?
Answer
The microorganisms already living in the garden soil did it. In Activity 2.6 you saw that soil contains various kinds of microorganisms. Some of these — fungi and bacteria — act on the plant waste and slowly break it down into simpler, nutrient-rich manure.
Decomposition: microbes turn complex plant waste into simple nutrients, which go back to the soil (Fig. 2.10).
Why it happens: the peels are food for these microbes. To use that food they must first break the complex substances of the plant waste into simpler substances that are rich in nutrients — this process is called decomposition. What is left behind after they have fed is the dark, nutrient-rich manure. The nutrients then dissolve into the soil and help plants grow better.
Did you know? This is exactly why gardeners collect dry leaves and plant waste and put them into pits — to make natural manure. The same helpful bacteria can also decompose animal wastes like dung.