My theory on G-cells now shall be addressed. Godzilla's cells are know for their resiliance and ability to replicate incredibly fast thus healing him instantaneously. Yet, all of the secrets of Godzilla's cells have yet to be unlocked.
Godzilla's cells are probably in the state they are beacuse of a certain number of reasons, I present to you now a theory why they are like they are. Godzillasaurus, the pre-G dino, had an isolated chromosomal trait inbedded in his DNA. It just lay there in his cell's nucleus without purpose or use in an unrefined, raw form for all his life, until....... Dateline 1954, the hydrogen bomb is detonated near Lagos island bombarding the island with massive dosses of radiation.
Godzillasaur's body is designed to be resistant to ill side effects of radiation but not mutation. Thus these gamma rays hit him and rearrange his DNA to cause his chromosomeal DNA to become self replicating to the point where his cells self replicate many times by themselves without breaking down. The cells began to replicate quickly, causing the growth of G's body to excelerate at amazing speed. The Organizer G-1 in G's cells was formed during this(it's the mutated Chromosome).
With it's new properties the G-cell was immune to sickness and most bacterial infections(the exception is the A.N.E.B. in Biollante) and did not need sustainance except from radioactive materials. Godzilla was now basically immortal and invulnerable because of this great power that he now attained.
Godzilla's cells also have the secret of reforming the living world if a catastrophic event ever would annihilate most of the living things on the planet. Godzilla's cells would survive and be the seeds to restart life.
Oki, people the original G died in 1954 right? Then why did he reappear? Here's my ideas how Godzilla could have survived and how there could be another Godzillas.
Oki Theory #1 states that Godzilla was not totally destroyed by the Oxygen Destroyer device. Several cells may have existed like the brain cell. The brain cell even though it's a highly specialized cell but somehow G's regenerative secret may be found in brain and heart cells. These specialized cells during the rapid mitosis may be able to rewrite the genetic instructions in the newly forming cells. This would transform them in any form of cell they were reprogrammed to form.
This would be more linked to the brain cells.
Then G's surviving cells could have reformed and Showa Goji was created the same thing could have happened after a long time and exposure to modern nukes would have recreated H. Series Goji.
Another theory states that there are probably 2 Godzillas; one gets terminated by the O2 Destroyer and the other surfaces later. This would mean that there are a breeding pair and that shows were the first Baby Godzilla comes from. Yet in the second series when the futurians take Godzillasaurus out of the past Godzilla never existed....or did it? This is a radical theory, but it states why somethings remained from the first G film during the post-futurian incursion.
The First G does appear and then the futurians know about that and send go back to the reconstructed Tokyo and somehwo use a method to mind wipe the people of Earth(probably with staelites that self destruct after mission is completed)to believe that Gojira is real....remember they manipulate time so they could wipe out all of the proof of G's appearence after the ruined cities have been rebuilt.
But why would they go to that much trouble? Here are some reasons:
1) The fear of G would lead to future anti-kaiju weapons taht would threaten King Ghidorah's assaults.
2)The fear of G would make Japan more militarialstic perhaps, and they want Japan as weak as it could.
And then they returned 1 moment after they left creating the illusion that they never left. Then when G resurfaced people saw G and the mindwiping effect on the people that were exposed to it was broken. Yet that's only a theory. It would explain Destroyah's appearence in the post-futurian time.
The secret to Biollante's immortality is X13. This is the 13th gene on its X chromosome. This is referred to as the "immortal genome" as it has been discovered to contain genetic imprints of Biollante's immortal resporation(the reason it keeps coming back indefinantly). This chromosome was discovered by Prof. Tannacore(oki Mark I mentioned ya where's my 5 bucks?!). He speculates the only way to kill Biollante would probably lie in its own cells, or the cells of Godzilla himself.