Which medical professional deals with diseases of the lower part of the large intestine?

The correct response identifies a proctologist as the medical professional specializing in diseases of the lower part of the large intestine. Proctologists focus on diagnosing and treating conditions that affect the rectum and anus, which are integral components of the lower gastrointestinal tract. Their expertise includes various disorders such as hemorrhoids, anal fissures, and cancers of the lower bowel.

In contrast, other options provided do not align with the specific focus on lower gastrointestinal diseases. A mortician is involved in the preparation of the deceased for burial and doesn’t engage in medical treatment. A physiatrist specializes in physical medicine and rehabilitation, often focusing on recovery from injury or illness but not specifically the diseases of the bowel. A pediatrician is a medical doctor focusing on children's health and does not have the specialized training required to treat diseases of the large intestine. Thus, the role of a proctologist is essential for patients suffering from lower gastrointestinal issues, making it the correct choice.