Identify $P, Q$, and $R$ in the given diagram of the male reproductive system of a cockroach.

The gizzard of a cockroach is a part of which system?

The heart of a cockroach is........

The body cavity of a cockroach is also called:

How many Malpighian tubules are present at the junction of midgut and hindgut in a cockroach?

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.