The Northeast did not agree with the Mexican War.
213,000 can be rewritten as 2.13*10^5. This tells us that it has has 3 significant digits.
Your correct answer is b. It has three significant figures.
Geographic means physicals features of the land in this case you look at only the negatives of this like big bodies of water mountains and steep terrain these made it difficult because some settlers didn't have horses or were traveling in large groups wich could contain elderly and young children
