The answer is an abdominal cavity.
The abdominal cavity refers to a space that comprises various essential organs including the stomach, the lower part of the esophagus, colon, small intestine, gallbladder, liver, rectum, bladder, spleen, and kidneys.
The abdominal cavity is a big cavity found in humans and various other animals. It is a component of abdominopelvic cavity. It is situated above the pelvic cavity and below the thoracic cavity. Its dome-shaped roof is the thoracic diaphragm, a thin sheet of muscles beneath the lungs, and its floor is the pelvic inlet, opening into the pelvis.
Bias , it's called bias which is basically wanting one turn out so you support it more even in an experiment
I believe it would be 18 feet..