Final answer:
Both algae and seed plants have chloroplasts, enabling them to perform photosynthesis. Other features like vascular tissues and pollen are not common between them.
Step-by-step explanation:
The characteristic shared by algae and seed plants is D) chloroplasts. Both algae and seed plants possess chloroplasts, which contain chlorophyll and enable the process of photosynthesis. This is a crucial adaptation that allows them to convert light energy into chemical energy, fueling their growth and development.
Other features such as vascular tissue, roots, pollen, and structures for embryo development within gametangia are not shared between algae and seed plants, as algae typically do not possess these complex structures that are more characteristic of terrestrial life forms. While algal ancestors gave rise to plant life, the evolutionary path has led to seed plants developing more complex adaptations such as seeds, pollen, and vascular tissues that are necessary for life on land.