[Jam930]

that's a pointless theory,

the thing is that plants fit on this planet, humans do not. I think if anything is foreign it's humans. or some aliens influence could have mutated us into smart people.

If you think plant seeds were dropped off by some meteor, well they wouldn't survive in space. at all.

vacuum, very very cold, etc. I think it would have to had been facilitated, aliens would have to deliberately drop off life, or life was started by lightning striking ponds of weird chemicals or whatever that other theory was.

Or if you're lazy,

God did it all.