In a population of bison, the birth rate over one year is fourteen. No bison immigrate into the population that year. Twenty bison die during the harsh winter, and ten more leave the population in search of more food. What has occurred in this population over one year?The size of the population has increased. The size of he population has decreased. The size of the population has remained the same.

( 1 ) The size of the population has increased.
( 2 ) The size of the population has decreased.
( 3 )The size of the population has remained the same.