These are mountains that have a hole at the top.

The hole of the volcano is called _____.

Hot melted rock can come out of the crater when the volcano goes off.

It is the melted rock inside the volcano.

It is the sudden shaking off the ground.

It is a large amount of water that quickly covers land not usually covered by water.

It is when the side of a hill or mountain falls down.

It is the breaking up of rocks.

It happens when soil, sand, and small bits of a rock are removed.

It happens when wind and water drop sand, soil, and small bits of rock in a new place.

It is a long wall built to hold back ocean water.

It is a short wall along a river.

It is a row of objects that blocks the wind.

Plants can stop soil erosion on slopes and hills.

Levees protect farm fields and cities.

Levees are usually made of soil, sand, and rocks.

People build dam to make dry land out of land that used to be underwater.

People and animals can erode rock and dirt on a mountain when they walk on it.

Volcano eruption can changed Earth slowly.