Why were the 1300s a century of crisis?

Which of these works from the italian renaissance exhibits contrapposto?

Someone who accepted the beliefs of social darwinism would have also agreed with which of these statements?

How were the okanogan highlands formed? a. by subduction, which caused huge folds in earths surface b. as a result of retreating glaciers carving great valleys into the earth c. when molten rock from under the earth approached the surface d. when the collision of volcanic island chains and ocean rocks formed new earth