Which law explains how rockets are launched into space?

Hint: Newton’s third law of motion states that for every action there is an equal and opposite reaction such that if object A exerts some force on object B then object B will also exert equal and opposite force on object A.

Complete step by step answer:
Newton’s third law of motion explains how rockets are launched into space. For example, when you jump on the ground your legs apply a force to the ground and the reason why your legs propel into the air afterward is the equal and opposite force applied by the ground.
A similar example of such type of motion is of a skateboard and a rider. Suppose both are in the state of rest, i.e., not moving and suddenly the rider jumps off from the skateboard, which according to the third law of motion is known as action. The skateboard will then react to this action by moving in the opposite direction.
Similarly, when the rocket lifts from the launch pad, the gas is expelled out of the engine. The rocket pushes on the gas in the downward direction and in turn the gas pushes on the rocket in the opposite direction. Here the action is when the gas is expelled out of the engine and the reaction is when the rocket is moved in the opposite direction.

Note:
For the rocket to lift from the launch pad, the action which is expelling the gas out of the engine must be greater than the mass of the rocket. However, in space, the tiny actions can move the direction of the rocket.