Consider the following statements
1. As per the optimum theory of population per capita income will increase with the population growth in underpopulated areas.
2. According to Malthus, Population doubles once in every 20 years.
3. Celibacy, self-control and late marriages are the preventive checks postulated by Malthus.
4. According to Malthus, war earthquake and flood are some of the positive checks on population growth.
Of these statements