Assertion (A): The peristaltic movements occur all along the gut.

Reason (R): The lining of the gut has muscles that contract rhythmically to push the food in regulated manner.

NCERT states: 'It is necessary to move the food in a regulated manner along the digestive tube so that it can be processed properly in each part. The lining of canal has muscles that contract rhythmically in order to push the food forward. These peristaltic movements occur all along the gut.'

Assertion (A) is true. Peristaltic movements do occur all along the gut, from the oesophagus to the intestines, ensuring food is moved forward in a regulated manner.

Reason (R) is true and is the correct explanation. The gut lining's muscles contracting rhythmically is precisely what constitutes and causes peristalsis — R directly explains the mechanism behind A's statement.

Option A — Correct. Both statements are true, and R correctly explains why peristalsis occurs all along the gut (it is caused by the rhythmic contraction of the muscles lining the canal).

Option B — Incorrect, because R is not merely a true but unrelated statement — it is in fact the direct mechanistic explanation for A.

Option C — Incorrect, because R is also true, not false; the gut lining genuinely contains muscles that contract rhythmically.

Option D — Incorrect, because A is true (peristalsis does occur throughout the gut), not false.