Question

Why does gravity cause layers of sediment to be horizontal

Answer 1

Answer: As more of the sediment is added it is compressed and then turns hard into rock layers.

Step-by-step explanation:

Answer 2

The truth about this is that all across the earth's surface there is gravity. So what happens is that sediments will deposit parrele on Earth's surface which is horizontal. Basicaly explained, As more sediment is added, it is compressed and then it is hardened into rock layers.