Studying geography reveals human history.
The U.S. federal system consits of a national government and what other government level
regional level
Answer:
The blank would be River
Explanation:
"River deltas are important in human civilization, as they are major agricultural production centers and population centers. They can provide coastline defense and can impact drinking water supply. They are also ecologically important, with different species' assemblages depending on their landscape position."
Hope this helps
The water is in gaseous form
