Neither a or b
Both a and b
Sea floor spreading
He had come up with a lot of other bad ideas in his life time.
He did not have enough evidence to support his theory.
He was thought to have mental problems.
He had too much evidence.
Similar rock structures were found on different continents.
The Appalachian Mountains looked completely different than the mountains on Greenland.
Fossils were found in the rocks.
None of the above.