A sound wave traveling downward with a speed of about 4,000 m/s suddenly slows to 1,500 m/s not far below from earth’s surface. What has the sound wave most likely encountered

A. to determine if humans can explore mars safely

You would need to take a picture so i can see

In atoms, the electron carries a negative elementary or unit charge; the proton carries a positive charge. the two types of charge are equal and opposite. in an atom of matter, an electrical charge occurs whenever the number of protons in the nucleus differs from the number of electrons surrounding that nucleus.