All such animals as hares, rabbits, and deer.
Of what use is the acute hearing to these animals?
It enables them quickly to hear the approach of their enemies, so that they may run away in time to escape the danger.
Conduction of Sound.
How does sound come to our ears?
Sound is carried to our ears by the air.
Is the air a conductor of sound?
Yes; the air is a conductor of sound.
Is there any sound where there is no air?
No; there is not any sound where there is no air.