Why did diseases from africa affect people in the americas in the early 1500s?

a some people from the americas had traveled to africa.
b africans were brought to the americas as enslaved people.
c africans moved to the americas voluntarily.
d europeans intentionally carried african diseases to the americas.

In what way did expansion and global trade during the 15th to 18th centuries affect the economies of european countries

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.

What are some incentives that parties have to carry out their campaign promises?