Question

sedimentary rock is formed from loose grains of minerals or other rock. these loose grains are called sediment, and they are formed through weathering and erosion.
weathering breaks down rocks into sediment. water, wind, ice, and living things can all cause weathering. during weathering, sediment is not moved away from the place where it forms.
however, during erosion, sediment is moved from the place where it formed. erosion happens when water, wind, or ice moves existing sediment, or creates new sediment and moves it somewhere else.
read the examples of how sediment can form. select the example that describes erosion.
tree roots grew between small cracks in a rock. as the roots grew bigger, they broke the rock apart.
rainwater collected in a crack in a rock and froze. the water expanded as it froze, splitting the rock into smaller pieces.
as a glacier moved over rock, ice at the bottom of the glacier ground the rock down into sediment. this sediment was carried away by the glacier.

Explanation:

To determine erosion, we use the definition: erosion moves sediment from its formation place.

• First example: Tree roots break rock (weathering, no movement).
• Second example: Water freezes to split rock (weathering, no movement).
• Third example: Glacier grinds rock into sediment and carries it away (movement of sediment, so erosion).

Answer:

The example describing erosion is: "As a glacier moved over rock, ice at the bottom of the glacier ground the rock down into sediment. This sediment was carried away by the glacier."