<em><u>Answer:</u></em>
a) Tobacco
<u><em>Explanation:</em></u>
Native Americans were smoking well before Columbus arrived. When Columbus saw the tobacco seeds, he took some with him back to Europe. Agriculturists planted these seeds and started to develop tobacco as an unwinding drug. Spaniards and a few Europeans smoked hand-moved cigarettes during the 1600s.
There are two main types of voting systems that can lead to different party systems. These are “first past the post” or “winner take all” systems on the one hand and proportional representation systems on the other. Each of these will tend to lead to a different type of party system.
D. It allows citizens of many European countries to freely travel across the continent.
It was over Religious conflict.