Bangladesh is a unitary and sovereign country known as the Peoples' Republic of Bangladesh. Bangladesh emerged as an independent country on March 26, 1971, and its state language is Bengali. The geographical location of Bangladesh is on the northern side of the Bay of Bengal. Bangladesh is between 20° 34' and 26° 38' north latitude, and between 88° 01' and 92° 41' east longitude. The area of B. D. is 56977 square miles or 143,998 square km. It has 6 divisions, 64 districts, 490 thanas, and 4451 unions, all administrative units. The population of Bangladesh is 120 millions, with equal proportion of peoples are male and females. The annual population growth rate in Bangladesh is 1. 7% ( 1996 census) and it has a population density per sq km of 755 (1991 census). The literacy level of the country is 40% up to 7 years and above. The country has three main seasons winter(Nov-Feb), summer (March-June), and Monsoon (July-Oct). Climatic conditions of the country vary through the year. In winter, maximum temperature averages 29°C and minimum temperature 10°C to 11°C, while in summer maximum temperature averages 34°C and minimum 21°C. In the monsoon temperatures are like in summer, and in the monsoon season average rainfall is 1194mm to 3454 mm. Bangladesh is called a country of rivers because many many rivers cross the country. The main crops in Bangladesh are rice, wheat, jute, tea, tobacco, sugarcane, pulses, oilseeds, potato, spices, and vegetables.