Answer to Question 1
Runoff channels from old rivers and outflow channels from catastrophic flooding in the distant past. Recent mudflows down the sides of some canyons and crater walls suggest occasional eruptions of liquid water persist to this day, as imaged by the Global Surveyor. The Rovers in 2004 also found clear evidence of sedimentary rocks formed under water at both the landing sites, on opposite sides of the globe.
Answer to Question 2
This statement does not make sense because it uses the term light-year as a length of time, rather than as a distance.
A hypothesis that suggests an explanation of the function of the gene that is defective in patients
The structure of liquid water
How water moves through a tree
Bone Surface Markings: Head
A 400-g piece of metal at 120°C is dropped into a cup containing 450 g of water
Micrograph of toothbrush bristles scrubbing plaque on a tooth surface.