Final answer:
The ocean is divided into zones based on available sunlight, distance from shore, and water depth. These factors are crucial for defining where different types of marine life can be found, such as in the photic zone, which is conducive to photosynthesis and thus supports more life.
Step-by-step explanation:
The ocean is divided into distinct zones that support various forms of marine life, which can be categorized based on several factors. The correct answer to the student's question is A: available sunlight, distance from shore, and water depth are the three main factors used to define these marine zones. By considering these factors, scientists can describe the habitat preferences of different marine organisms, as well as the physical conditions present in each zone.
For example, the photic zone is rich in sunlight and supports a high level of photosynthesis, leading to a greater abundance of life. Photosynthetic organisms are typically found in the intertidal zone and the upper parts of the neritic zone, where sunlight penetration is sufficient for photosynthesis. In contrast, the aphotic zone lacks sunlight and is inhabited by organisms that are adapted to the dark, such as bioluminescent species.