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

Explain the digestive system of cockroach with the help of a labelled sketch.

The figure given below shows the male reproductive system of a cockroach. Identify $P$,$Q$,and $R$.

Which of the following statement$(s)$ is/are correct about the nervous system of a cockroach?
$(i)$ It consists of a series of fused segmentally arranged ganglia joined by paired longitudinal connectives on the ventral side.
$(ii)$ There are six ganglia lie in the thorax,and three in the abdomen.
$(iii)$ The sense organs are antennae,eyes,maxillary palps,labial palps,and anal cerci,etc.
$(iv)$ Each eye consists of about $5000$ hexagonal ommatidia.

Explain how excretion takes place in a cockroach.

Which is the correct sequence of labeling for the given figure?