Dogs have specialized evaporative cooling in the respiratory tract by

The correct option is panting.

Unlike humans, dogs have very few sweat glands (located mainly on their paw pads) and cannot cool their bodies through perspiration. Instead, they rely on a specialized mechanism called panting for thermoregulation and evaporative cooling.

When a dog's body temperature rises, it initiates panting—a pattern of rapid, shallow breathing. During this process, air is moved quickly over the moist tissues of the tongue, mouth, and upper respiratory tract.
This rapid airflow accelerates the evaporation of moisture from these wet surfaces. As the liquid water evaporates and turns into water vapor, it absorbs latent heat from the surrounding blood vessels in the mouth and respiratory tract, effectively cooling the blood circulating through the body and helping to lower the dog's core temperature.