This is a thought question. Answering thought questions require an answer made up of complete sentences. Copying text from the book is not acceptable.

To prepare your answer try the following

• Jot down a list of facts or results of calculations which can be used to answer the question.
• Organize the list.
• Write the individual items of this list as sentences.
• Organize these sentences into a well written paragraph (which can be as short as two sentences).
• You may wish to write a rough draft and revise it. Some people find it easier to do this using a word processing program.