Today, Mars would be a dry desert with little to no water on its surface, with the exception of a small amount of ice at its poles.
Mars' appearance millions of years ago was very different today. Given that it once had a lot of liquid water on its surface in the form of rivers and lakes, it may have even resembled Earth.
This leads scientists to the conclusion that although there is definitely no life on Mars right now, there may have once been microbial life there.
Four of the 12 samples collected as part of the rover's second research mission were from the river delta, a particularly intriguing area in Jezero.
This area, which was formerly a delta where debris from a river was thrown, is a fantastic place to search for evidence of life.
NASA's assistant administrator for science, Thomas Zurbuchen, stated: "We selected the Jezero Crater for Perseverance to examine