Humans like theories. It allows them to think outside the box, be creative and bring purpose to life. In this timeline, humans are trying to figure out the meaning of life and their place in it - to learn through meaningful experience and to help others find truth as the ladder (latter) ascends.
There is a theory called Panspermia - the hypothesis that "seeds of life" exist across the universe - and that life on Earth and other planets may have originated through the dispersement of these seeds.
There is a theory about ancient aliens responsible for the seeding of life on this and other planets, for any number of reasons.
There is a theory that God created humans and there is truth to religious doctrine.
There is a theory that the "seeds of life" follow a specific universal blueprint encoded in their genetic design. Today we call that code sacred geometry.
All, or none, of these theories may be correct or they could all blend into each other, aligned with others we don't know exist. Your intuition should be telling you to stop guessing as we are about to find out the truth.
When it comes to Mars, I've heard many theories from science to pseudoscience. Do gray aliens have a base on Mars? Are humans their biogenetic experiment to regain emotions? Is all of it just a myth in the hologram (illusion) of our reality? Is the face on Mars an alien linked to the creation of humans or are we just scrying natural formations in the quest for answers?
Earth life 'may have come from Mars' BBC - August 28, 2013
Life may have started on Mars before arriving on Earth, a major scientific conference has heard. New research supports an idea that the Red Planet was a better place to kick-start biology billions of years ago than the early Earth was. The evidence is based on how the first molecules necessary for life were assembled.