Please help me! I don't know!

How did the construction of the erie canal improve transportation in the united states in the 1820s? a. the canal connected the great lakes to the mississippi river. b. the canal connected the great lakes to the ohio river. c. the canal connected the atlantic and pacific oceans. d. the canal connected the great lakes to the atlantic ocean.

Were african-americans allowed to serve in the military in wwi? explain

Which of the following improved u.s. relations with china? a. the open door policy b. the boxer rebellion c. the burlingame treaty d. the chinese exclusion ac