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'.
i. Year 1921 was known as demographic divide because there was decrease is decrease there is decrease in death rate and increase in birth rate. The change started after the passing of the influenza pandemic.
ii. During the 30 years of period 1951 - 81 due to decrease in death rate the population growth rate led to the population explosion. In this period India's population increased from 251 to 361 million with growth of 47.3 percent.
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 .