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

In cockroach,nephrocytes are concerned with

Which of the following statement$(s)$ is/are correct regarding the excretory system of a cockroach?
$(i)$ Excretion is performed by Malpighian tubules.
$(ii)$ They absorb nitrogenous waste products and convert them into uric acid,which is excreted out through the hindgut.
$(iii)$ In addition,fat body,nephrocytes,and urecose glands also help in excretion.

Which of the following statements is incorrect?

Blood of $Periplaneta$ does not carry oxygen because

What is the position of the testis in Periplaneta americana?