The features that makes locomotion in water easy for fish is the

The feature that makes locomotion in water easy for fish is their streamlined body shape. This means that their body is long and thin, with a pointed head and tapered tail, allowing them to move through the water with minimal resistance. This streamlined body shape helps reduce drag, which is the force that resists motion through a fluid, making it easier for fish to swim efficiently. In addition, some fish have a lateral line, which is a sensory system that detects changes in water pressure and helps fish navigate and locate prey. The scaly and slimy bodies of fish also provide protection and help reduce friction as they move through the water, but they are not as essential to fish locomotion as their streamlined body shape.