In which two ways do paragraphs 4-7 contribute to the reader's understanding of the passage. Story: Restoring forests by Karena Phan.

A. They show how a government can improve its actions.
B. They demonstrate how the planet has changed over time.
C. They reveal that trees are used by doctors to heal patients.
D. They explain why nonnative trees cause problems in certain areas.
E. They provide background information on the struggle of landowners.

D. They explain why nonnative trees cause problems in certain areas.

E. They provide background information on the struggle of landowners.