Which continent was once joined with greenland? how do you know?

Denmark owns Greenland, but it is marked as part of North America on maps. Looking at how continental drift works, it is more likely that it was more recently part of North America.

North America (during the continental breakup known as Laurasia) was once connected to Greenland. Due to the continental breakup and the constant shiftting of the earth's plates (albeit at only about five millimeters a year) Greenland must have been connected geographically to North America at one point in history.

Coniferous forest ecosystem

Ice melting no wait thats global warming