An angiosperm is different from a gymnosperm in the absence of
A. Vascular tissue
B. Ovary
C. Seed
D. Naked ovule

Hint: Angiosperms and gymnosperms are both seed-bearing plants. Gymnosperms are commonly known as naked seed plants. Angiosperms have seeds enclosed within an ovary.

Complete answer:
The angiosperms, also called flowering plants are vascular plants bearing the seeds enclosed in mature ovaries or fruits. The life cycle of angiosperms is seasonal- they die during autumn. For reproduction, they rely on pollinators such as bees. Fruit trees like Pear, Mango, Apple and Orange show flowers before they bear fruits. Grains like Wheat and Rice are examples of angiosperms. Plants like Tomato, Roses and Petunias are also angiosperms. The seeds of angiosperms develop in the ovaries of flowers and are protected inside the fruit. Xylem of angiosperms has vessels. Companion cells are present in the phloem. The diversity of angiosperms is greater than the gymnosperms.

Gymnosperms have uncovered seeds directly on the sporophyll.The seeds are developed on the surface of scales and leaves, which often grow to form a cone or stall shape. Since their seeds are bare and not enclosed, they are also known as naked seed plants. Gymnosperms are evergreen. They mostly rely on wind for pollination as their seeds are open to the air. Pine, cedar, cycads, juniper are some of the examples. They are usually formed in unisexual cones, known as strobili. They lack fruits and flowers. Unlike angiosperms, gymnosperms lack both vessels and companion cells.
So an angiosperm is different from a gymnosperm as its seeds are not naked, but covered by a fruit.

Hence, the correct answer is option (D)

Note: Angiosperms have various pollination strategies that are not found among the gymnosperms. That is why angiosperms are more diverse.Gymnosperms are known as the ancestors of angiosperms that were known to exist 140 million years ago. Flowering plants evolved with modifications in various organs like flowers, leaves, stems, endosperm, etc.