Was Mars alive or not in the past?

The image above) Mars that it looks today. You can see the dark Greenland-shaped area on the northern side of that planet. There is a possibility that this Greenland-shaped structure is the result of the asteroid impact. 

If that asteroid impacted the ancient Martian sea, that covered the entire northern area of that planet. That asteroid turned the water into overheated plasma. And that impact destroyed the primitive organisms that lived in that sea. 

That same or similar impact would also melt the entire mantle of that planet. And that thing could destroy all genetic material from the primitive prokaryotic bacteria that could live in that sea. 

The fact is that there was no oxygen in the young Mars' atmosphere. That means those hypothetical organisms did not exist for a long time. Maybe they had no time to release a remarkable mass of oxygen into that planet's atmosphere. The end of those organisms was meteorite impact. 

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But in some theories, there is a small possibility to find active bacteria on Mars. 

That those bacteria lurk under Mars's surface. The volcanic activity on Mars means that there is a possibility that deep under the core of the Red Planet could be active bacteria that can use volcanic temperature as an energy source. 

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Were there some bacteria on ancient Mars?

Maybe the samples that the Perseverance probe sends to Earth will solve that question. There is the possibility that Mars' atmosphere was not oxygen almost at all in the past. But there was some kind of sea. And then we must realize that in the history of Earth, the young Earth had no free oxygen in its atmosphere. The first cells and photosynthetic bacteria released oxygen into the atmosphere. 

And maybe similar things could happen on Mars. But then some kind of meteorite or comic impact destroyed that planet. There is the possibility that life on Mars was not very advanced. And in another model, those prokaryotic bacteria-level organisms didn't have time to create oxygen in the Martian atmosphere. And all that oxygen was in that ocean far away in the past. 

"An artist’s illustration of the InSight lander on Mars. InSight, short for Interior Exploration using Seismic Investigations, Geodesy and Heat Transport, was designed to give the Red Planet its first thorough checkup since it formed 4.5 billion years ago. Credit: ​​NASA/JPL-Caltech" (ScitechDaily.com/Massive Marsquake! Five Times Larger Than Previous Record Holder)

The suspected lifeforms on Red Planet were not very highly advanced. They could be prokaryotes that lived in that ancient ocean. 

At this point, we must realize that Earth is not Mars. If some lifeforms lived on Mars. That doesn't mean they would not be higher level than some procaryotic bacteria. In some speculations, life on Mars has just begun. There is the possibility that the genomes of those extremely primitive organisms were in the form of RNA. 

And then the meteorite ended that story. Maybe that meteorite moved Mars to a new trajectory. In that theory, the lifeforms on that planet were like some kind of cyanobacteria. The end of that alien bacteria was some cosmic catastrophe. 

There is the possibility that a large asteroid impacted Mars' sea. That impact happened at interplanetary speed. 

And it just turned that ocean to plasma. And that plasma could destroy all genetic material on that planet. 

There is a possibility that even those samples that Perseverance brings on Earth would not give a straight answer to that question. Maybe, the heat of impact destroyed those hypothetical alien bacteria's  RNA and other genetic material when Mars lost its core.

https://phys.org/news/2022-12-experimentalists-oxygen-required-minerals-mars.html

https://scitechdaily.com/ancient-mars-may-have-been-teeming-with-life-until-it-drove-climate-change-that-caused-its-demise/

https://scitechdaily.com/life-on-mars-ancient-bacteria-might-lurk-beneath-mars-surface/

https://scitechdaily.com/life-on-mars-latest-intriguing-organic-findings-by-nasas-perseverance-rover/

https://en.wikipedia.org/wiki/Mars_ocean_hypothesis