Answer:
1-) Wegner looked at the coastline of Africa and saw it fir together with the coastline of South America, he then noticed several more continents fitting together like a big puzzle
2-) he found fossils of plants/animals in countries where the climate did not allow the fossilized animal/plant to survive
3-) Wegner saw how the mountains and rocks in South America matched the mountains/rocks in Africa(this would have been impossible had pangea not occured since Africa and South America were a whole ocean apart)