What evidence do we have that there was running (liquid) water on Mars in the past? Astronomy

On September 27, 2012, NASA scientists announced that the Curiosity rover found direct evidence for an ancient streambed in Gale Crater, suggesting an ancient "vigorous flow" of water on Mars. In particular, analysis of the now dry streambed indicated that the water ran at 3.3 km/h (0.92 m/s), possibly at hip-depth. Similar to Earth's canyons- Planetary scientists have long marveled at ancient evidence of flowing water carved in the Martian surface — gigantic canyons, tendrils of winding river channels and deltas where the rivers disgorged sediments into lakes. Since both Earth and Mars have canyons that indicate a river used to flow there.

photosynthesis makes the glucose that is used in cellular respiration to make atp. the glucose is then turned back into carbon dioxide, which is used in photosynthesis. while water is broken down to form oxygen during photosynthesis, in cellular respiration oxygen is combined with hydrogen to form water.