Answer:
Weight and reaction.
Explanation:
With respect to Newton's third law of motion, action and reaction have equal magnitude but acts in opposite direction.
Thus, the brick of mass 10 kg has its weight (due to gravitational pull of the earth), which acts downwards through its center of mass. This makes the scale to produce an opposing force of equal magnitude, which acts upwards. These two forces acting in opposite directions balancing each other.
The two forces acting on the brick are: its weight and the reaction from the scale.
