Speed can be thought of as the rate at which an object covers distance. ... Speed has the dimensions of distance divided by time. The SI unit of speed is the metre per second, but the most common unit of speed in everyday usage is the kilometre per hour or, in the US and the UK, miles per hour........?
The answer is Prove a hypothesis
High frequency, as humans cannot hear the sound of the bats using echolocation because of it's such high frequency.
Hope this helps :)
