Answer:
When Harry S. Truman ran for president in 1948, several factors supposedly were working against him: the media, Republican candidate Thomas E. Dewey's popularity, and Truman's own down-to-earth style.
Explanation:
Colons are used before a list of items, which in this case are the factors working against Harry S. Truman.
The answer to the given question above would be the last option. Based on the given two sentences above, the punctuation and/or conjunction that can be used to combine them would be this: desert; the average. So here is the combined sentence. The interior of Antarctica is a windy polar desert; the <span>average precipitation is less than two inches each year. Hope this helps.</span>