It seems all life on Earth is related, so maybe either there is a God or some parallel universe. Why would we be derived from more than one living thing?
Well, it seems we're not; A central part of evolution theory (with a substantial amount of evidence behind it) involves common descent, i.e.: that all life on earth has a single common ancestor (sometimes called the LUCA, for Last Universal Common Ancestor). Through evolution, life then diversified over billions of years into the different forms we know today. Evidence for the LUCA idea comes mainly from molecular biology; for example, all life shares the same genetic code (by which DNA is translated into proteins), the same basic metabolic processes (by which cells generate energy), the same types of cell membranes, the same molecular structure for its DNA and RNA, and so on. It seems it didn't have to turn out that way, and in fact scientists have (for example) synthesized DNA with different molecular "backbones" that seem to function just fine. The simplest, most likely explanation for the evidence we have is common descent.
That doesn't necessarily mean that life only originated once, though; maybe there were many independent origins, but the LUCA simply outcompeted (or ate) all the other ones, and they went extinct. It may even have been the case that life repeatedly originated and then went completely extinct again, only to originate again on the early earth. Or maybe it really did only happen once. Hard to say.
That living thing could have come on some meteor, tho I do not know how meteors work.
Meteoroids are basically rocks or dust grains floating around in space. When they get captured by the earth's gravity, they fall down into the atmosphere. At that point, they're called meteors. Because they're traveling really fast (typically more than 20 km/s), there is a lot of friction with the atmosphere, causing the outside of the meteor to glow and break apart. The dust trail it leaves behind is the "shooting star" that you see. Most meteors are really just small dust grains, and completely vaporize, but if one is large enough, a piece of it may impact the surface of the earth, and then its called a meteorite.
it seems like life is like a virus.
Well viruses are sort of in between living and nonliving. For example, viruses do not have their own metabolism, and they cannot reproduce by themselves. They're basically just a strand of DNA or RNA with a protein coating that protects them and helps them enter a host cell. The host cell actually does all the hard work for them. It's not entirely clear how viruses evolved, but some may have started out as so-called "plasmids", which are little bits of DNA or RNA that bacteria sometimes share with each other (they play a role in bacterial resistance to antibiotics, among other things).
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