Sound waves can be used in a similar way to "see" things. After turning on a sound source, we can look at the pattern of reflected sound waves that bounce back to us. Our own ears and brain don't process sound into mental pictures.
It is B because the other ones are good.
Answer: The magnitude of force per length that each wire exert on the other wire is 2.67×10^-5 N/m.
The force is repulsive.
Explanation: Please see the attachments below
Wings to fly. Without flying, birds would be near defenseless.