Fossils , silicone just guessed sorry
In eukaryotes, there are two distinct types of cell division: a vegetative division, whereby each daughter cell is genetically identical to the parent cell (mitosis) and a reproductive cell division, whereby the number of chromosomes in the daughter cells is reduced by half to produce Haploid gametes (meiosis)
The carbon that plants need for photosynthesis comes from carbon dioxide, or CO2 that's present in our atmosphere. Hope it helps
thats dirty bruh but you could filter all the dirty stuff out and reuse the water