- last post: 01.01.0001 12:00 AM PDT
My idea is they came up with many ways of killing the flood, but the flood, (my opinion, not being overly to complex) evolved to grow immune to many weapons or ways of killing it, that the only way would be to starve them to death.
And for the organisms, they evolve in thousands of years, some, (in this case, the covenant) evolve more quickly than others, but, it is possible that the species that made the covenant were not yet, sentient, thus, after the halo's activated, the species evolved to grow into sentients, and thus, many races were born.
[Edited on 11/10/2006]