In gymnosperms, the ovules are described as "naked" because they are not enclosed within a carpel or an ovary, unlike in angiosperms. Gymnosperms lack true carpels, which are the specialized structures that enclose the ovules in flowering plants. This is why the ovules are exposed directly to the environment, allowing pollen to land directly on them for fertilization. Other options are incorrect : fertilization does occur in gymnosperms, archegonia are present in most gymnosperms, and endosperm is absent only in the sense of being formed after fertilization, but this is not the reason ovules are naked.