An ultrasound can produce the image of a fetus by using waves that are labeled as "ultrasound waves" or in ultrasonic frequency.
This may seem like an odd concept but you should note that everything we see and hear is made up of waves, like light and sound, that are at different frequencies.
The reason why there are different color lights are because there are different type of frequencies. Some frequencies, such as ultrasonic, we can not see with our human eye.<span />
One of the challenges that scientists face when classifying a new fossil is that any tiny detail is all that separates one species from another. Further exploration is required to identify another set of characteristics that may help in deciding which organism belongs or create a new class.
