Scientists say Martian rock may hold evidence of life

Researchers say they have identified rocks that could hold four-billion-year-old evidence of life on Mars.

According to a scientific article published Friday, scrutiny of clay-carbonate rocks in the Nili Fossae region of Mars points to possible evidence of organisms that once lived on the Red Planet.

In 2008, NASA's Mars Reconnaissance Orbiter determined that the Nili Fossae, a region of valleys that have cut into the Martian bedrock, contains carbonate.