Answer:
I'm not a genius ok?
Explanation:
1. Radar communication, Analysis of the molecular and atomic structure, telephone communication
2. c
The answer to ur question is: B
Sorry could not remember formula so had to derive it but the answer is shown at the bottom of photo
It does make sound, just because there are no receptors does not mean that an object does not make sound. For example, whales communicate ona frequency higher then our ears can hear, however, we know that they still make sound. Another example is thunder; If you were far away to see thunder but not hear it, does it make sound? It does. Objects make sound by vibrating, there is no connection to sound and the presence of a receptor.
