Gymnosperms and Angiosperms Are Believed to Be More Closely Related

Gymnosperms and angiosperms are believed to be more closely related to one another than the other major plant groups because

A) they alone possess vascular systems.
B) both groups produce separate male and female gametes.
C) they provide their embryos with stored food that can support growth before photosynthesis begins.
D) both groups protect their seeds within protective structures.