Trade increased in europe because of the interest in eastern goods created by
1. marco polo's book
2. recapture of constantinople by the byzantines
3. the crusades
4. both marco polo's book and the crusades

Two gymnastics teams are intense rivals. the first team has started recruiting new gymnasts from different cities and even foreign countires in an effort to build a stronger team. after learning this, the secondteam begins its own recruitment campaign to find better gymnasts. over a period of months, each team recruits dozens of players, each time trying to find a better recruit than its rivals most recent addition. which idea from the cold war is most similar to this scenario