Can Mars sustain life?

According to NASA, 7 billion years ago, Mars may have been an excellent place for microbes to live, but currently it cannot support life because the air is too thin and is comprised mainly of carbon dioxide. After drilling into the rocks on Mars, scientists discovered the key ingredients of life, including sulfur, nitrogen, hydrogen, oxygen and carbon.

The surface of Mars is cold and dry, and it has been battered by the radiation from space. Scientists believe that approximately 3 billion years ago the atmosphere was thicker, the weather was warmer and drinkable water was flowing on the surface.