Identify the odd one out.

Which of the following parts is not associated with the nerve ring in a cockroach?

Corpora allata are removed from a nymph. It will

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.

The figure below shows the digestive system of a cockroach. What are $P$ and $Q$?

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