Whats a sound? i need help lol

In physics sound is a vibration that propagates as an acoustic wave so a transmission medium such as gas liquid or solid and human physiology and psychology sound is the reception In physics sound is a vibration that problem that propagates as an acoustic wave so a transmission medium such as gas liquid or solid and human physiology and psychology sound is the reception of waves of such waves and their In physics sound is a vibration that problem that propagates as an acoustic wave so a transmission medium such as gas liquid or solid and human physiology and psychology sound is the reception of waves of such waves and their perception by the brain sound ways between 20 Hz known as infrasound

step-by-step explanation:

answer: c.  

step-by-step explanation:

mixtures containing substances that get attracted to magnet can be separated using a magnet. we can separate iron from a mixture of sand and iron, as only iron attracts to the magnet.