MCQ Detailed View

Every disease, whether simple or complex, always has a cause. In biology and medicine, a disease is defined as an abnormal condition that negatively affects the structure or function of part or all of an organism. For this abnormal condition to exist, there must be an underlying reason or factor — the cause.

The cause of a disease may vary. For infectious diseases, the cause is usually microorganisms such as bacteria, viruses, fungi, or parasites. For example, tuberculosis is caused by Mycobacterium tuberculosis and influenza is caused by influenza viruses. In these cases, the germs act as the direct cause of illness.

However, not all diseases are infectious. Some diseases are caused by genetic factors, such as sickle-cell anemia or hemophilia, which are inherited conditions. Others are caused by lifestyle factors, including poor diet, lack of exercise, smoking, or stress. Diseases like diabetes, hypertension, and heart disease often result from a combination of genetic predisposition and lifestyle choices.

Environmental factors also play a role in causing disease. Exposure to radiation, toxins, or pollutants can lead to cancer or respiratory problems. Even nutritional deficiencies, like lack of vitamin D leading to rickets, are recognized as causes of disease.

It is important to understand that while some diseases may have cures, and many involve germs or require a patient, the only universal truth is that every disease must have a cause. Without a cause, the disease cannot be scientifically explained, diagnosed, or treated.

In summary, the correct answer is cause, since it is the fundamental basis for the existence of any disease. Identifying the cause is always the first step in prevention, diagnosis, and treatment in the field of biology and medicine.