The Columbian Exchange is the name given to the items shared between the New World and the Old World. Once European exploration began, items passed both ways. Which of the following explains the result this exchange had on many Native Americans living in North and South America?
A.
Native Americans began using tobacco.
B.
Native Americans died because of diseases.
C.
Native Americans gave livestock to Europe.
D.
Native Americans started growing corn.

1- is the product of two rational numbers irrational or rational? first, make a hypothesis by multiplying two rational numbers. then, use variables such as x=a/b and y=c/d and the closure property of integers to prove your hypothesis. 2- what do you think the product of a nonzero rational number and an irrational number is? is it rational or irrational? make use of variables, the closure property of integers, and possibly a proof by contradiction to prove your hypothesis. 3- why do we have to specify that the rational number must be nonzero when we determine what the product of a nonzero rational number and an irrational number is? if the rational number were 0, would it give us the same result we found in part b?