Answer:
Step-by-step explanation:
According to Newton's third law, for every action, there is an equal and opposite reaction. This means that if force A acts on object B, then there must be a force that object B exerts on object A that is equal in magnitude but opposite in direction. Therefore, the two forces that are a Newton's third law pair are P and Q, as they are the forces that the parachute and the man exert on each other in opposite directions.
R and S are not a Newton's third law pair because they are not acting on the same objects. R is the force of the Earth on the parachute, while S is the force of the man on the parachute. These forces are not equal and opposite, as they are acting on different objects.