Curiosity has a few clues, found life on Mars in a distant past indeed been possible. Although there are so few clues, the Mars probe is no evidence to be able to deliver of life on the red planet.
Curiosity found on Mars organic molecules containing the building blocks for life, says space agency NASA. In the molecules that Curiosity took out powder from a rock that NASA employees Cumberland have mentioned, there are more carbon and hydrogen. NASA mentions that organic molecules could indicate life, but that also can exist without there ever life on Mars.
In addition to the organic molecules, the Mars rover, a peak in the methane concentration in the atmosphere measured. At the beginning of 2014 was seven at the billion particles in the atmosphere of methane, ten times as much as in other periods.
From both directions leads NASA that there is ‘favourable conditions’ have been on Mars to support life. Curiosity rover landed in 2012 on Mars, and has as a mission to discover whether there was ever life on the red planet. In addition, the Mars rover measurements as preparation for a mission to Mars with people; which should be sometime in the next thirty years.