High and low tides are caused by the moon. The moon's gravitational pull generates something called the tidal force. The tidal force causes Earth—and its water—to bulge out on the side closest to the moon and the side farthest from the moon. These bulges of water are high tides.
Answer: 19th century observers had noticed that the coastlines of North America and South America generally matched the coastlines of Europe and Africa. B. A German climatologist named Alfred Wegener proposed scientific evidence to support the idea that the continents once fit together.
