Which is the correct sequence for ootheca formation in a cockroach?

Spiracles found in cockroach are

Of the following,which instrument is most commonly used to observe the external features of a grasshopper's abdomen?

The mouthparts of a $Cockroach$ are of which type?

Which of the following statement$(s)$ is/are correct regarding cockroaches?
$(i)$ The body of the cockroach is segmented and divisible into three distinct regions - head,thorax and abdomen.
$(ii)$ Blood vascular system is of closed type.
$(iii)$ They are monoecious and both sexes have well developed reproductive organs.
$(iv)$ The development of $P. americana$ is paurometabolous,meaning there is development through nymphal stage.

Find out the incorrect statement: