If something happens to the seed supply, or the terminator gene mutates, it may irretrievably break the plant-seed-plant cycle that has supported most life on Earth.
(something; happens; to the seed supply, or the terminator gene mutates) (it; may irretrievably break; the plant-seed-plant cycle that has supported most life on Earth) (the plant-seed-plant cycle; has supported; most life on Earth)
something it the plant-seed-plant cycle
happens may irretrievably break has supported
to the seed supply, or the terminator gene mutates
the plant-seed-plant cycle that has supported most life on Earth
most life on Earth