Which of the following structures in a cockroach are made up of chitin?

Phallic organs in cockroach are related to

Which of the following statement$(s)$ is/are correct regarding the respiratory system of a cockroach?
$(i)$ It consists of a network of trachea that open through $12$ pairs of small holes called spiracles present on the lateral side of the body.
$(ii)$ Thin branching tubes carry oxygen from the air to all the parts.
$(iii)$ The opening of the spiracles is regulated by sphincters.
$(iv)$ Exchange of gases takes place at the tracheoles by diffusion.

Identify the correct sequence of organs in the digestive system of a cockroach.

In a cockroach,from where do the hepatic caecae arise?

In cockroaches,during the digestion of food,the enzyme cellulase is synthesized by: