Chemical experiments have been carried out by the rover Curiosity, which NASA landed on our neighboring planet 14 years ago.
In ground samples, researchers have identified more than 20 organic molecules, several of which have not been found on Mars before.
What we see are the building blocks of life - prebiotic chemistry on Mars - that have been preserved in these rocks for billions of years, says astrobiologist Amy Williams, who led the study.
The findings do not prove that life has existed on Mars - for that, scientists believe they need to study Martian samples on Earth. However, the successful tests with the test tubes carried by the rover are considered promising for planned follow-ups using the same method (called TMAH) on Mars and on Saturn's moon Titan.
