The first paragraph of this press release from NASA-JPL,Missing Piece Inspires New Look at Mars Puzzle, says it all,
Experiments prompted by a 2008 surprise from NASA’s Phoenix Mars Lander suggest that soil examined by NASA’s Viking Mars landers in 1976 may have contained carbon-based chemical building blocks of life.
While the release goes on to state that the evidence for life on Mars is not conclusive, none-the-less, the goal post has moved considerably since the days when no building-blocks for life were thought to exist on Mars. Life on Mars…even the thought is a fascinating notion.