Or perhaps life on Earth came from Mars. It's ballistically easier.
There could still be primitive life on Mars.
Technically, if we go to Mars there will be life there (us) to find. That seems like cheating, though.
The stellar wind can strip hydrogen from water leaving oxygen behind. With enough water you can get enough oxygen to oxidize everything, leaving some to be detected in the atmosphere.
On Linux it is becoming more and more difficult. I use a dark background with yellowish text but it is hard to find the settings on new installs.
There are no data that cannot be plotted on a straight line if the axis are chosen correctly.