Can you provide more details ?
<span>Stabilizing selection is at work in this case. This is the force that allows a population to gradually center on a mean value due to a presence of a non-extreme bodily trait. The more extreme examples of the trait lead to the organisms being selected out, and the trait that is the least conspicuous wins out in the long-run.</span>
The animal that can hear 67,000 hertz is a dog !!
