Answer:
Sound bounces off objects around you an travel close to your body. When sound reaches you the dome shape of your ears let's the sound travel down the ear canal and to your eardrum. When the sound reaches the brain I assume it processes and you assume a sound to what is making the sound. Like fire alarms for example, when we here that specific sound we know to react by evactuating.
Explanation:
I hope this helps, I used my general knowledge to answer.
