Which of the following is correct for the common cockroach ?

Options

A. Oxygen is transported by haemoglobin in blood
B. Nitrogenous excretory product is urea
C. The food is ground by mandibles and gizzard
D. Malpighian tubules are excretory organs projecting out from the colon

Answer

C

Explanation

In cockroach, mandibles are a pair of hard, strong, large, dark coloured triangular, structures which move in horizontal motion and crush food between them.
Gizzard or proventriculus has an outer layer of thick circular muscles and thick inner cuticle forming six highly chitinous plate called teeth. The gizzard acts as the grinding chamber and helps in grinding the food particles.