Answer:
may be
the discovery of new evidence
Explanation:
Accepted theories may be modified or overturned as new evidence and perspective emerges. Scientists are likely to accept a new or modified theory if it explains everything the old theory did and more. The process of theory change may take time and involve controversy, but eventually the scientific explanation that is more accurate will be accepted.
The last option: over tens of millions of years, the giant supercontinent Pangaea began to slowly drift apart forming the continents
