Why do skydivers have a terminal velocity?

People and things keep doing the same thing until a force makes them change according to Newton.

When a skydiver jumps out of a plane they have zero velocity downwards but the force of gravity is pulling them downwards back to Earth. This force, acting on the mass of the skydiver causes them to accelerate downwards at 9.81m/s^2. The skydiver will accelerate downards and get faster and faster but a second force, wind resistance, will get bigger and bigger the faster they go and will act to slow them down. This opposes the force of gravity. At some point the force of wind resistance slowing the skydiver down will be as large as the force of gravity pulling the skydiver down to Earth. Here there is no net force on the skydiver and it is known as equilibirum. The skydiver is at their terminal velocity because there is no net force causing them to speed up or slow down - until they open their parachute.