The basic feature of the disease risk covered by health insurance is ().

Answer: a, c, e

The risks covered by health insurance are mainly human health (disease) risks. To constitute a disease referred to in health insurance, the following three conditions must be met: ① the disease is caused by the insured's own internal reasons, not by obvious external factors; ② Diseases are not caused by long-standing reasons, but by accidental reasons; ③ The disease is caused by non-congenital causes.