Find out the correct sentence about manure:
$(i)$ Manure contains large quantities of organic matter and small quantities of nutrients.
$(ii)$ It increases the water holding capacity of sandy soil.
$(iii)$ It helps in draining out excess water from clayey soil.
$(iv)$ Its excessive use pollutes the environment because it is made of animal excretory waste.

When Ashok visited his village,he observed that villagers were suffering from malnutrition. To curb malnutrition in the village,he suggested they select five or six fish species in a pond. This increased the fish yield from the pond. The villagers were surprised to see the results and asked him to help with the other two ponds in the village.
$(i)$ What name is given to this intensive fish farming?
$(ii)$ Write the basis on which the different fish species are selected.
$(iii)$ Ashok's initiative is worth praising. Give two reasons.

Which one of the following nutrients is not available in fertilizers?

Vividha told Vasudha that she will show her some magic. Vividha took a metallic pipe. She asked Vasudha to hold one of its ends close to her ears. She gently tapped the other end of the pipe with a metallic object. She asked Vasudha what she heard. Vasudha said she heard two sounds.
$(a)$ Was this magic? Why did Vasudha hear two sounds?
$(b)$ What values are imbibed by Vividha?

Differentiate between inland fisheries and marine fisheries.

Define $(i)$ Vermicompost,$(ii)$ Green manure,and $(iii)$ Biofertilizer.