A skydiver prepares to jump out of a plane. Explain how gravity and air resistance will affect motion of the skydiver before and after he or she opens the parachute

First, he will start to accelerate. The constant pull of gravity on the body will cause it to go faster. At a sudden moment, the air resistance will stop the acceleration (Newton's 3rd law), thus having a maximum speed (I think it is about 270 - 300 km/h)