What distinguishes gymnosperms from angiosperms?

Gymnosperms are characterized by their reproductive structures, which do not include flowers. Instead, gymnosperms produce seeds that are exposed on cones or other structures, rather than being enclosed within a fruit. This absence of flowers is a key distinguishing feature when compared to angiosperms, which are known for producing flowers and fruit as part of their reproductive process. The other options refer to aspects like seed production or floral structures that directly differentiate angiosperms from gymnosperms, reinforcing the importance of flowers in the latter's classification. Additionally, while water requirements can vary among plant species, they do not specifically distinguish gymnosperms from angiosperms. Thus, the defining characteristic of gymnosperms is their lack of flowers.