Well, when a plant or animal dies in a damp environment it will most likely get buried in mud or silt. The tissues over time will decompose and leave bones or shells behind ( depending on what was there originally it can vary) Eventually over time sediment builds up and hardens into rock.
I sincerely hope this helps you ~
The order that the nucleotides are arranged in form different "codes" to create traits. RNA in humans is used for transporting, and making the amino acid proteins. The order of amino acid proteins also changes the polypeptide formed, and changes more traits, and characteristics. Basically, it's like reading a book. Each book is made up of the same 26 letters, but their all arranged in different orders. You can find the some of the same words in another book, but no two books are exactly alike. All the letters and words are arranged in different ways, even though other books have the same letters and words.
It should be 3 or 6... Not 100% sure.
The plant would no longer put out oxygen, and the concentration of carbon.