The <em><u>correct answer</u></em> is:
The union of two sets is a combination of all elements from both sets. The intersection of two sets, on the other hand, is a set of the elements common to both sets.
For instance, if we have the sets {1, 3, 5, 7, 9} and {3, 6, 9, 12, 15}, the union would be the combination of both:
{1, 3, 5, 6, 7, 9, 12, 15}
The intersection of the sets would be the common elements. The only elements that are in both sets are 3 and 9. This makes the intersection
{3, 9}
