A differential diagnosis is based on which of the following?

While data from body tissues can provide valuable information, it does not encompass the entirety of the differential diagnosis process. This option overlooks the critical role that symptom comparison plays in identifying or ruling out various diseases, making it insufficient as a standalone basis for diagnosis.

An external examination is just one aspect of the diagnostic process and may not reveal all relevant information about a patient's condition. Relying solely on external examinations ignores the need for a comprehensive analysis of symptoms and patient history, which are essential for making an accurate differential diagnosis.

Focusing exclusively on the patient's symptoms neglects the importance of comparing those symptoms with other similar diseases. A thorough differential diagnosis requires considering a broader range of potential conditions, which involves comparing symptoms rather than solely relying on what the patient reports.

The presence of stressed lesions may provide insights into specific conditions, but it does not represent the comprehensive approach necessary for a differential diagnosis. Identifying lesions alone does not encompass the full spectrum of symptoms and comparisons needed to differentiate between diseases effectively.