Explain the following :
i. The year 1921 is known as the 'demographic divide'.
ii. The period during the years 1951 - 1981 is often referred to as the period of 'population explosion'.
Give three positive consequences of migration.
i. It brings new ideas related to good education, technology, family planning etc.
ii. Migration results in intermixing of diverse cultures.
iii. It breaks narrow considerations widens the mental horizon of the people.
Despite tank irrigation being a simple form of irrigation, it is not used by all farmers. Explain Why.
i. Today the need to conserve water resources has become greater that ever. Explain.
ii. Mention two steps that need to be undertaken for the conservation of water resources.
i. What geographical conditions are required for the growth of wheat?
ii. Compare wheat cultivation in India and China - with reference to the varieties grown .