Sound waves are sent out buy the animal/or vessel using sonar and the animal/vessel uses the echo from the original Soundwave that was sent out to determine the distance and size of the object that it hit
I'd say the most questionable source of health information is D. A health care professional because people are more of a reliable source than websites. A health care professional is also trained to do these certain things.
-rhear
the answer is C it prevents bonding between baby and caregiver
