The number of abdominal segments in male and female cockroaches is . . . . . . .

The characteristic feature that distinguishes between male and female cockroaches is .........

On an average,female $Periplaneta$ produces $.......$ oothecae,each containing $......$ eggs. Choose the correct option which fills the blanks respectively.

The type of egg found in a cockroach is known as?

Explain: Cockroach is harmful for human beings.

Ommatidia serve the purpose of photoreception in