How do weeds survive?

Multiple methods of reproduction, proximity to resources and tolerances of extreme air, soil and weather extremes are reasons why weeds survive. Weeds generally can be counted upon to reproduce by such means as prolific seeding and quick rooting of rhizomes, root and stem fragments and stolons. They also tend to have fibrous, near-surface roots that grab light, moisture and nutrients and to have high tolerances of drought, floods, freezes, heat and pollution.