What was the demographic impact of the Columbian Exchange on the populations of the Old World?

a. Population growth across the Old World based on New World crops such as corn and the potato
b. Massive depopulation of Western Europe due to the migration of the Americas
c. Sharp increase in the West African population to furnish individuals for the slave trade
d. Sharp decrease in male populations as many sailors died at sea
e. Greatly increased life expectancy aided by new medicinal plants from New World tropical rainforests

Answer: a. Population growth across the Old World based on New World crops such as corn and the potato