Thunder formation during thunderstorms

Thunder is produced by lightning, which causes a rapid expansion of air along its path, creating a shock wave that we hear as sound. Statement 1 is incorrect because the meeting of cumulonimbus clouds does not produce thunder. Statement 2 is misleading because lightning doesn't separate clouds but is the electrical discharge itself; moreover, it's the shock wave from the discharge expansion that creates thunder, not the lightning separating clouds. Statement 3 is incorrect because violent upward movement of air and water particles causes cloud formation but not thunder. Thunder is specifically the acoustic phenomenon resulting from the explosive expansion of air heated by lightning. > Thunder = sound wave from lightning's rapid air expansion, not from cloud interactions or atmospheric movement.