People can change earth

_______ along the river could protect Nate's city from floods.

• Levees

• Weathering

• Erosion

When people make changes to land like building houses or roads, do they cause erosion?

• Yes, they do.

• No, they do not.

Was this Hoover Dam built by people?

• Yes, it was.

• No, was not.

Can people built a structure to stop volcanoes?

• Yes, they can.

• No, they cannot.

What is the easiest way to prevent wind in this picture?

• Build a wall

• Plant trees

• Cover it with a big plastic sheet

Why do we need dams? (choose 2 answers)

• to bring water to the cities

• to prevent (stop) floods

• to hold back ocean water

A dike holds back ocean water. Which pictures shows a dike?

• 
• 
• 
• 

A windbreak blocks the wind. Which pictures shows a windbreak?

• 
• 
• 
• 

A farmer tries to slow down erosion on the land. The wind is blowing the soil away.

What could the farmer do to help stop the soil from blowing away?

• build a windbreak

• cut down trees

• build a levee

• dig a tunnel

Look at the picture. It shows one way people change Earth.

What is the main purpose of the wall?

• it blocks wind

• it stops flooding

• it protects the road

• it causes weathering