Back in the 19th century to the early 20th century, how many states were there in the u. s and what year did the u. s begin to have a total of 50 states?

Alaska was purchased from Russia for 7.2 million and Hawaii agreed to join the United States as the 50th state in 1959

Explanation:

That is the answer

ba geologist finds four sedimentary rock she determines that no geologic events have shifted the layers she labeles them a,b,c,dbfrom top to bottom