Research on the physiological basis of hunger has indicated that

A) there is no relationship between stomach contractions and the experience of hunger.
B) hunger continues in humans whose cancerous stomachs have been removed.
C) rats whose stomachs have been removed must be force-fed to prevent starvation.
D) the secretion of ghrelin is reduced when the stomach is empty.

Research has shown that humans whose cancerous stomachs have been removed continue to experience hunger, indicating that hunger is not solely based on stomach contractions. Additionally, rats whose stomachs have been removed require force-feeding to prevent starvation. The secretion of ghrelin, a hunger-stimulating hormone, actually increases when the stomach is empty, not decreases.