The three phases of population growth are:
1st phase: slow growth phase, both birth and death rates are high, the population is small.
2nd phase: fast growth phase, birth rate stays high and can increase because the population increases, but death rate decreases because the population is still far from the carrying capacity of the environment.
3rd phase: equilibrium phase, the curve of growth reaches the environment carrying capacity, the number of organisms of the population stays stable and the birth and death rates become closely equal.