They both hold back ice from changing the shape of the land.

They both hold back wind from changing the shape of the land.

They both hold back water from chnging the shape of the land.

Sandbags are used for changes that happen quickly.

Dikes are used for changes that happen quickly.

Dikes

Sandbags

Grasses and flowers look pretty so the wind and water does not bother them.

Grasses and flowers hold down the soil and protect soil from the force of the wind and water.

Water flows from high places to low places.

Water flows up to high places.

Water flows up to the top of high mountains