sentences:  Features called recurring slope lineae are thought to be caused by flows of brine — hydrated salts.In July 2018, scientists from the Italian Space Agency reported the detection of a subglacial lake on Mars, below the southern polar ice cap, and spanning horizontally, the first evidence for a stable body of liquid water on the planet.Because the temperature at the base of the polar cap is estimated at , scientists assume that the water may remain liquid by the antifreeze effect of magnesium and calcium perchlorates.