Which of the following is NOT an aquatic organism?

The correct answer is based on the habitat and ecological classification of the organisms listed. Fish, frogs, and crabs are all primarily associated with aquatic environments. Fish live in water throughout their life cycle, frogs generally require aquatic habitats for reproduction, and crabs are primarily marine creatures that inhabit ocean floors or coastal areas.

In contrast, the eagle is a terrestrial bird, primarily adapted for life in the air and on land. Although eagles may be found near water bodies where they hunt for fish, they do not depend on aquatic environments for their existence and can thrive in various terrestrial ecosystems. Therefore, when identifying which of the listed organisms is not aquatic, the eagle stands out as it is not an organism that primarily inhabits or relies on aquatic ecosystems.