Thay are on high towers because if it was below how would the water flow. Putting it on high towers gives you an advantage of the gravity with means you got free pressure without having to use a pump.
<span>Water pressure = Height * density * gravity</span>
If you count the number of seconds between the flash of lightning and the sound of thunder, and then divide by 5, you'll get the distance in miles to the lightning: 5 seconds = 1 mile, 15 seconds = 3 miles, 0 seconds = very close. Keep in mind that you should be in a safe place while counting.
If the two waves combine to produce ANY wave that smaller
than either of the originals, that's destructive interference.
99% of the earth´s atmosphere by mass is made up of only these elements: Nitrogen and oxygen.
Answer: B) Nitrogen and oxygen.