The answer is gravity. I hope this helps.
To find average speed, we divide the distance of travel (in this case, 400 metres) by the time she took, 32 seconds. Therefore: 12.5 seconds is her average speed.
Answer:
it is atoms and molecules
Mid ocean ridges
The mountain ranges in the middle of the oceans
Sea floor spreading
The process by which new, oceanic crust forms along a mid ocean ridge and older crust moves away from the ridge. :)