What is the function of the Malpighian tubules in a cockroach?

In cockroach,the development is paurometabolous,meaning that development occurs through the nymphal stage. The nymph grows by moulting about $13$ times to reach the adult form. The metamorphosis process in cockroach requires approximately how many days?

Select the correct sequence of organs in the alimentary canal of a cockroach starting from the mouth.

Which of the following structures does not help in excretion in the cockroach?

What is the position of the testis in Periplaneta americana?

In female cockroaches,the $Gynovalvular$ plates are modifications of which of the following?