Describe variation in the speed of sound through various media.

Light is a transverse wave because its components vibrate perpendicular to the direction of propagation. It has an electric and a magnetic property, so it is EM wave which is transverse in nature.

Where as, sound waves are longitudinal waves and the particles of the medium move parallel to the direction that the pulse moves.

So, as sound waves moves parallel in direction of pulse so, it is affected by media, whereas light waves don't need medium to travel as they are em waves and transversal in nature that is perpendicular motion.