I think it is option (C).
If the answer is helpful then mark me as brainly.
Answer:
Atomic number
Explanation:
Hope it helps you in your learning process.
The layer of electrically charged molecules and atoms which spans 40-250 miles above ground called ionosphere causes the display of the aurora and the reflection of radio waves back to earth.
To determine what the cyclists average speed is, simply divide the distance the cyclist has travelled by the time the cyclist has traveled for.
Assuming that this is the average rate the cyclist is moving at it would be 12 km/hr.
<span>c. low frequency and low energy</span>
