What does the term "conformation" refer to in horses?

The term "conformation" specifically refers to the physical shape and structure of a horse's body. It encompasses the arrangement of bones, muscle, and tissues that determine the overall build and symmetry of the horse. Good conformation is essential for the horse's health, performance, and ability to move efficiently. Horses with well-balanced conformation are generally considered more athletic and capable of performing at higher levels in various disciplines.

In the context of the other options, performance abilities relate to how well a horse can execute tasks or compete, which is influenced by conformation but is not the definition of the term itself. The color and markings of a horse fall under breed standards and aesthetics, rather than its structural attributes. Lastly, the temperament of a horse pertains to its behavior and personality traits, which do not directly relate to the physical structure of the animal. Thus, the focus on physical shape and body structure makes the first option the correct answer.