Give a brief account of some signs that indicate that there has been water on the Martian surface

Question

What will be an ideal response?

Answer 1

Several types of formations hint that there has been water on the Martian surface. Outflow channels on the Martian surface appear to have been cut by massive floods carrying as much as 10,000 times the volume of water flowing down the Mississippi River. Such floods apparently swept away landscape features and eroded deep channels. The number of craters formed on top of the outflow channels shows that they are billions of years old.Valley networks look like meandering river beds that probably formed over long periods. The valley networks are located in the heavily cratered southern hemisphere.There are many other signs that indicate that there has been water on the Martian surface, some of which are geologically recent. The regions of collapsed terrain on Mars appear to be places where subsurface water has drained away. Gullies leading downhill appear to have been eroded recently, judging from their lack of craters, and a few gullies have been seen to appear between one Martian year and the next. In 2015, the Mars Reconnaissance Orbiter made spectroscopic observations confirming present-day seasonal groundwater flows.