Ecdysone is produced by

What is the function of Malpighian tubules in a cockroach?

Define the following terms:
$(i)$ Vermicomposting
$(ii)$ Haemolymph

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.

Tracheae of cockroach and mammal are similar in having

In cockroach,which of the following is the principal motor centre?