What is the structural adaptation on a seahorse?

The correct answer is: A tail used for grasping.

Seahorses have a number of unique structural adaptations that help them survive in their environment. These adaptations include:

* A prehensile tail: Seahorses have a long, muscular tail that they use to grasp onto seaweed and other objects. This helps them to stay in place in the water and avoid being swept away by currents.

* A bony armor: Seahorses have a bony armor that protects their bodies from predators. This armor is made up of interlocking plates that are covered in small spines.

* A camouflage coloration: Seahorses have a variety of coloration that helps them to camouflage themselves against their surroundings. This makes it difficult for predators to spot them.

* A long snout: Seahorses have a long snout that they use to suck up food. This snout is also used to inject venom into their prey.