Although the fertility rate for women in the United States has declined in recent years to a value below replacement level, the United States population is still increasing because of

The answer to your question is Immigration.

Explanation:

Although, the fertility rate for women in the United States has declined in the recent years to a value below replacement level, the United States population is still increasing because of Immigration. Immigration has grown tremendesly in the past few years because people are coming to the United States to find jobs.

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