As they evolved and adapted, those of the fittest survived to reproduce. Those that did not adapt, died.
The amplitude of a sound<span> wave </span>determines<span> its </span>loudness<span> or volume. A larger amplitude means a louder </span>sound<span>, and a smaller amplitude means a softer </span><span>sound</span>
Balance:
a book resting on a table
a car driving at 10 miles per hour in constant velocity
a cat sitting on a chair
a bulb that attach to the ceiling
your grandma sleeping on a bed
Unbalance:
your brother sprinting across the kitchen
a ball rolling at 5 m/s^2
your mom trying to run at 2 m/s^2 to spank you
you dropping your coffee mug on a floor
a cat jumping out of your bed
a tear from your eye falling through the floor
Hope this helps