What defines gymnosperms?

Gymnosperms are defined as plants that have unprotected seeds, which are typically found on the surface of cone scales rather than enclosed within an ovary as in angiosperms (flowering plants). This characteristic is a fundamental distinction of gymnosperms, setting them apart from other plant categories. The presence of exposed seeds allows for a specific mode of reproduction and seed dispersal that is different from that of flowering plants.

In contrast, the other options describe plants that do not fit the definition of gymnosperms. For instance, plants with seeds inside ovaries refer specifically to angiosperms, while nonwoody plants with smooth stems do not accurately characterize gymnosperms, which include many woody species. Lastly, flowering plants that produce fruits are also angiosperms, making them distinct from gymnosperms.