Why can't audible sound be used to create an image like ultrasound? Why does it have to be ultrasound?

Which property of fossils allow scientists to determine the relative rock ages..

In what direction does the medium move relative to the direction of the wave? explain.

(01.02 mc) nicole pushes her bike up a hill. overhead, the sun exerts a gravitational force on earth. which statement is true about the bike and earth? they both experience contact forces. they both experience non-contact forces. the bike experiences a non-contact force and earth experiences a contact force. the bike experiences a contact force and earth experiences a non-contact force. they both experience non-contact forces.