Final answer:
The correct option to complete the statement is c. Copepoda.
The subclass of crustaceans that dominates the primary consumer level in aquatic communities is the Copepoda. These small but numerous organisms play a critical role in the food chain and ecosystem function.
Step-by-step explanation:
The subclass of crustaceans that is of extreme ecological importance, often dominating the primary consumer level in aquatic communities, is known as the Copepoda. These tiny crustaceans are crucial in the food chain, serving as a primary source of nutrition for many larger animals. Copepodas are incredibly numerous, and they exist in various aquatic environments, including fresh and salt water. They hold a significant ecological role by recycling nutrients and being a key food source for many species, contributing to the biological pump that helps sequester carbon in the deep sea.
Copepods can exhibit both herbivorous and carnivorous feeding behaviors. While some consume phytoplankton, others may prey on smaller zooplankton. Diversity in the Copepoda subclass allows them to exploit a range of ecological niches and maintain their dominance as primary consumers in aquatic ecosystems.
Therefore, the correct option to complete the statement is c. Copepoda.