What defines angiosperms in terms of seed characteristics?

Angiosperms are defined by having seeds that are enclosed within a fruit. This characteristic distinguishes them from other plant groups, such as gymnosperms, which have seeds that are exposed and not enclosed in a fruit. The enclosure of the seeds in angiosperms not only protects them but also aids in their dispersal, as the fruit can attract animals that will help spread the seeds to new locations. This unique feature plays a significant role in the reproductive success and diversity of angiosperms, allowing them to adapt to various environments and promote a wide range of plant forms.