According to Newton's 3rd law, In every action there is always an equal and opposite reaction: or the forces of two bodies on each other are always equal and are directed in opposite directions. Meaning that forces always occur in pairs. Consider the ff examples:
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).
Hope this help..