NASA says its "Perseverance" Mars rover has found potential signs of ancient life on the red planet. In rock samples collected last year from what's thought to be an ancient lake bed, evidence of possible microbial activity was found. NASA officials likened the rock formations to "fossils" and said it's the best evidence yet that living organisms may have long ago existed on our neighboring planet. Chapters: 0:00 NASA finds potential evidence of life on Mars 0:38 Mike Tice, Geobiologist at