What's the gravity and motion

Gravity : Gravity is the force acting on objects that pulls it to the crust of the earth. It is the universal force of attraction between all matter.

Motion: Motion is the movement of objects from one position to another.

acid rain does not usually kill trees directly. instead, it is more likely to weaken the trees by damaging their leaves, limiting the nutrients available to them, or poisoning them with toxic substances slowly released from the soil. the main atmospheric pollutants that affect trees are nitrates and sulphates.