Which symptom may indicate distention?

Swelling or being swollen out of shape is the correct symptom that may indicate distention. Distention refers to an abnormal enlargement or swelling of a particular area, often associated with the abdomen, due to an accumulation of gas, fluid, or other substances. When the abdomen becomes distended, it often appears visibly larger or swollen, which aligns directly with the choice of "swelling or being swollen out of shape."

The other symptoms listed—heart palpitation, excessive sweating, and nausea—are common in various medical conditions but do not specifically indicate distention. Heart palpitations are related to cardiovascular issues, excessive sweating may be associated with anxiety or hyperhidrosis, and nausea can result from various gastrointestinal disturbances but does not directly reflect the physical manifestation of distention. Thus, the choice highlighting swelling accurately captures the essence of what distention presents in a clinical context.