Final answer:
Orexigenic agents stimulate appetite (answer c), relevant to processes in the hypothalamus that regulate feeding behavior and hunger suppression.
Step-by-step explanation:
The term orexigenic refers to substances or signals in the body that stimulate appetite. Based on this definition, the correct answer to the question provided would be: c. Appetite stimulant. Orexigenic agents can influence feeding behavior by interacting with specific pathways in the brain, such as those involving the hypothalamus, which plays a key role in regulating appetite.
Furthermore, the list of statements provided relates to different biological processes. For instance, gastrin—an important digestive hormone—affects the stomach by stimulating the release of stomach acid (a). The gastric phase mentioned in another statement (b) begins when food reaches the stomach, which triggers the release of several digestive secretions and the processing of ingested materials.
Another point discusses the hypothalamus and its role in suppressing hunger (d), which is the opposite of the orexigenic effect. Therefore, in the context of these statements, understanding the biological processes such as the release of digestive enzymes, hormonal regulation, and appetite control is crucial.