Final answer:
Taste and smell are called chemical senses because their receptors are sensitive to chemical molecules, and this sensitivity allows us to detect and interpret the flavor in food and other substances in our environment.
Step-by-step explanation:
Taste and smell are called chemical senses because A. Their receptors are sensitive to chemical molecules. Both gustation (taste) and olfaction (smell) involve chemoreceptors that respond to chemical molecules present in our environment. These receptors are located in the taste buds on the tongue and the nasal passages. When activated by the appropriate chemical stimuli from food or the air, these receptors send nerve impulses to the brain. The brain then interprets these signals, giving us the sensation of taste and smell which contribute to the perception of flavor.
The concept of taste and smell being interconnected is insightful, showing how both senses contribute to the flavor of food. For instance, sweet-tasting substances usually indicate calories, which are important for survival, while bitterness might signal toxicity, suggesting that the substance is harmful and should be avoided. Similarly, the sense of smell can alert an animal to the presence of food or other animals, or to dangerous chemicals in their environment.