Final answer:
The rectum, likely the intended subject of the student's question, is approximately 20.3 cm (8 in) long in humans, following the curved contour of the sacrum with features like rectal valves for fecal and gas separation.
Step-by-step explanation:
The rectal gland being asked about is likely a misnomer in the context of the question, and based on the provided information, the student might be referring to the rectum in humans. The rectum is the final section of the large intestine, terminating the alimentary canal, and according to the information provided, it measures approximately 20.3 cm (8 in) in length. It is important to note that the rectum follows the curved contour of the sacrum and contains three lateral bends with rectal valves which aid in separating feces from gas. These anatomical features are essential for the proper functioning of the rectum in the excretory system.