<span>A block placed at the summit of an arch or other structure, locking the whole together; a keystone.</span>
The correct answer is: A: He devised the theory of evolution
Answer:
an era in which the international slave trade was starting to grow, Columbus and his men enslaved many native inhabitants of the West Indies and subjected them to extreme violence and brutality. On his famous first voyage in 1492, Columbus landed on an unknown Caribbean island after an arduous three-month journey
