Efforts by NASA to search for signs of life on Mars have focused on the search for evidence of liquid water rather than looking
directly for biological organisms (living or fossilized). Use your
knowledge of the influence of water on life on Earth to construct
an argument justifying this approach.

the answer is lactic acid from anaerobic respiration. the acid in lactic acid is what creates sore and burning muscles. if you think about how acid burns that will give you a clue for questions like this.

imagine a line passing through the center of earth that goes through both the north pole and the south pole. this imaginary line is called an axis. earth spins around its axis, just as a top spins around its spindle. this spinning movement is called earth's rotation. at the same time that the earth spins on its axis, it also orbits, or revolves around the sun. this movement is called revolution.