You will be given a definition of a task first, then an example. Follow the example to solve a new instance of the task.
Given a scientific passage and an answer, generate a question for the given answer.

Passage: A frameshift mutation is a deletion or insertion of one or more nucleotides that changes the reading frame of the base sequence. Deletions remove nucleotides, and insertions add nucleotides. Consider the following sequence of bases in RNA:. Answer: nucleotides.
Solution: A frameshift mutation is a deletion or insertion of one or more of what that changes the reading frame of the base sequence?
Why? The science passage defines frame mutation and the main compoment here is nucleotides. Hence the generated question is apt.

New input: Passage: Anal Canal Finally, food residue reaches the last part of the large intestine, the anal canal, which is located in the perineum, completely outside of the abdominopelvic cavity. This 3.85 cm (1.52 in) long structure opens to the exterior of the body at the anus. The anal canal includes two sphincters. The internal anal sphincter is made of smooth muscle, and its contractions are involuntary. The external anal sphincter is made of skeletal muscle, which is under voluntary control. Except when defecating, both usually remain closed. Answer: large
Solution:
In humans, the anus is attached to what kind of intestine?