Learn About Diagrams Writers may use diagrams to give extra information or explain the text. A diagram is a picture or drawing that helps you interpret the information in nonfiction texts. Look at the diagram. Read the caption and the labels. The labels tell you what the layers of the Earth are, and the picture shows what the layers look like.

The Earth is made of many layers.

Crust

Mantle

Outer Core

Inner Core

Practice Together

Identify Information Look at the diagram on page 339 of “A Natural Balance.” This diagram shows what happens to a habitat when there is an oil spill. The labels identify the different parts of the diagram. Look at the first label, and answer these questions:

• 1. What is a tanker?

• 2. What causes a tanker to leak oil?

How does the first label help you understand the information about oil spills? How does the diagram and all its parts help you understand the main message in the selection?

Try It!

Interpret the Diagram Use the diagram in “A Natural Balance” to help you answer the following questions:

• 1. What is one cause of an oil spill?

• 2. How many workers helped clean up the oil spill?

• 3. What parts of the oil spill cleanup does the diagram show?

• 4. How are birds affected by the oil spill?

What other information do you get from the diagram that is not in the text? How do the diagram and the text work together to give you a clearer understanding of what harms a habitat? Discuss your ideas with a partner.