B. Seaweeds that use sunlight for photosynthesis
After a coral reef collapses, seaweeds that can quickly grow and compete for sunlight may be the first organisms to establish themselves in the ecosystem. They can outcompete other organisms that rely on photosynthesis, like corals, in nutrient-rich waters. This can lead to a shift in the ecosystem from a coral-dominated community to one dominated by seaweeds.