Q. The CORRECT statements about the digestive system of cockroach are,
I. The entire foregut of the cockroach is lined by the cuticle.
II. The midgut is broader than the hindgut of the cockroach.
III. The proventriculus of the cockroach has teeth for grinding food particles.
IV. The digestive juice is secreted by 100-150 hepatic caeca present at the junction of foregut and midgut.

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Solution:

The alimentary canal of cockroaches is divided into three regions, namely the foregut, midgut and the hindgut. The foregut has a thick layer of cuticle lying inside the outer layer of circular muscles. The midgut is not as broad as compared to the hindgut and the proventriculus (the expansion of the esophagus above the stomach) has chitinous plates (teeth) for grinding the food particles. The hindgut is broader than midgut and is differentiated into illeum, colon, rectum. The junction of the foregut and the midgut shows the presence of Malpighian tubules which help in excretion.