Cryptogams and Fanerogams
as it is a reproducing organ and if it does not exist there will no flowers
the seeds and runners (parts of the root)
The archegonium.
To me, the pollen grain of the male plant will pollinate to the stigma [either by self or cross pollination] to produce FRUIT.
From memory, the three categories are animal, plant and mineral.
Well, if a plant is rare, then reproducing will help keep the plant species going for years of study. Also, if a plant has been around for thousands of years(or more) then they are definitely worth reproducing for biologists and botanists to study. We can learn many things from plants like how they stay alive through the ice age or why and how they live wherever they live, and sometimes plants can even help with medicine. I know my family keeps an aloe vera plant on our counter for burns.
With vegatative propogation, taking plant parts, you will get the identical plant to the parent. Seed may vary.
There are six categories or "Kingdoms" today: 1) Animalia 2) Plantae 3) Fungi 4) Chromista 5) Protozoa 6) Bacteria
The 2 categories are 'pure substances' or 'mixtures'
...reproducing sexually (and from fruiting).
Animal and Plant
The Boll Weevil destroys the cotton plant by reproducing and laying it's eggs on it, in turn makes the eggs hatch and the baby Boll Weevils eat the plant for food