Scientists think that algae first evolved approximately 2.7 billion years ago, and soon after this oxygen began to exist in the atmosphere. Photosynthesis by primitive plants and algae released oxygen, which gradually built up in the atmosphere.
Explanation:
Hiram Bingham Discovers Lost Inca City of Machu Picchu. On July 24, 1911, Yale University professor Hiram Bingham discovered the ruins of Machu Picchu, one of the most significant archaeological finds in the history of the Americas.
Porque estabamos lejos de la revolución industrial, E.E.U.U fue un país muy beneficiado, esta revolución cmenzó en Gran Bretaña pero no llego a Colombia sino 100 años mas tarde cuando otros paises ya nos tenian ventaja.