a. In cockroach grinding of food particle is performed by gizzard.

Explanation: Gizzard in the cockroaches is defined as a muscular stomach which has teeth like structures which helps in grinding the food into smaller and simpler particles.

b. Malpighian tubules help in removal of Nitrogenous excretory products.

Explanation: The Malpighian tubules are responsible for removal of nitrogenous waste in cockroaches and also in osmoregulation. The Malpighian tubules absorb the nitrogenous waste products produced by the cockroach and then covert it to simpler uric acid for excretion.

c. Hind gut of cockroach is differentiated into ileum, colon and rectum.

Explanation: Hind gut has the three differentiated parts - ileum, colon and rectum which are mainly used for the reabsorption of nutrients.

d. In cockroach blood vessels open into spaces called Haemocoel.

Explanation: The blood vessels open into spaces known as the haemocoel which are further divided into sinuses.