Circulatory and Respiratory systems working together to provide body with oxygen.
Answer:
335 million years ago
Explanation:
Pangaea or Pangea ( /pænˈdʒiːə/) was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from earlier continental units approximately 335 million years ago, and began to break apart about 175 million years ago.
C. A buildup of lactic acid in the tissues.
