Can cultivated plants or weeds spread over the earth’s surface without human assistance?

Cultivated plants are plants bred by humans. They were selected according to the characteristics that we need. This often makes these plants defenseless in the wild. So cultivated plants are unlikely to be able to spread in the wild. If they appear there, it is not a fact that they will survive, and if so, they will lose those properties due to which they are considered cultural. Weeds can develop on their own, unless they are rigidly attached to some kind of crop.