you are carrying a heavy basket. you are exerting an upward force on it (action). examine your arm after laying the heavy basket. you will notice a small dent on the part where you hung your the basket - evidence that the basket also exerted a force on it (reaction)
birds fly by pushing the air below them (action).the air in turn pushes the bird upward (reaction)
a swimmer pushes the water backward (action) and the water pushes him forward (reaction).
Exerted by
Person on the ground