Answer:
The reaction force is the force exerted by your body on the earth pulling upwards.
Explanation:
This can be explained using Newton's third law of motion which states that if object A exerts a force on object B, object B exerts a force of equal magnitude and opposite direction on object A. One characteristics of these force are that they act o 2 different bodies. In this example, the earth exerts a force on you. The Newton's reaction force would be you exerting a force of equal magnitude on the earth.
