Final answer:
Seas have greater biodiversity than oceans because they offer more varied habitats such as coral reefs and estuaries.
Step-by-step explanation:
Oceans, seas, and other aquatic biomes differ in terms of their biodiversity due to various factors. One reason why seas often have greater biodiversity than oceans is because they provide more varied habitats (c). Seas are relatively shallow compared to oceans, which allows for different zones with distinct ecological conditions.
These zones create diverse habitats that support a wide range of species. For example, coral reefs in marine seas are unique ecosystems teeming with many different species. Estuaries, which are found where rivers meet the ocean, also contribute to the high biodiversity in seas by providing nourishment and shelter for many organisms.