1). In what industry do most Americans work?

2). How did California become the nation's most populous state?

3). How has the economy of the South changed?

4). How has U.S population shifted since the country began?

5). What helped the economy of the West to grow?

6). Why is the United States a leader in agricultural production?

My answers to these questions are the following:
1). Most Americans work in the service industry, which consists of occupations in the field of information processing, finance, medicine, transportation, and education.

2). California is the country's most populous state because of excellent farmland, good harbors, and a mild climate.

3). The economy of the South changed as it has attracted many manufacturing and service industries feeling the harsh weather of the "rust belt," causing it to become more industrialized.

4). ?

5). ?

6). ?

4. At the time of independence, the United States was all east of the Appalachians.

5. I added to your answer yesterday.

6.
http://www.usda.gov/wps/portal/usda/usdahome?navid=AGRI_PRODUCTION

Are my other answers correct?

Yes.

For the fifth question, my textbook doesn't state that transportation helped the Western economy to grow. It does, however, state that "many cities with good harbors, including Seattle, Los Angeles, and Long Beach, make foreign trade--especially with Asia--important."

O.K.

Is my previous answer correct, then?

Since your book says that, you must be right.