Who was the first
United States?

If you mean the first United States president, then it is George Washington. If you mean the first state, then it is Delaware.

Explanation:

George Washington was the first President, John Adams was the first Vice President, and Delaware was the first "state".

Explanation:

i think the answer is c, rivers.

explanation:

sometimes, borders fall along natural boundaries like rivers or mountain ranges. for example, the boundary between france and spain follows the crest of the pyrenees mountains. for part of its length, the boundary between the united states and mexico follows a river called the rio grande. the borders of four countries divide africa’s lake chad: niger, chad, cameroon, and nigeria.

brainliest is someone you pick by simply clicking a button. it only shows up if there are two people that answered your question, then you decide who answer more accurately with detail and explanation and you give that person the title "brainliest".

i hope this your understandings.