Answer to Question 1
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, so they must be very old as well.
Answer to Question 2
The large-impact hypothesis proposes that the Moon formed when an object estimated to have been at least as large as Mars smashed into the proto-Earth. Model calculations indicate that this collision would have ejected a disk of debris into orbit around Earth and that the debris could have quickly formed the Moon.
A very high-resolution texture of the planet Mars
Mars from Hubble Space Telescope October 28, 2005 with dust storm visible.
Craters on Mars
Viking Mars Lander
Water on Mars!
Proteins as Transport Channels