Each ovary in a cockroach is formed by a group of $8$ ovarian tubules or ovarioles,containing a chain of developing ova. Fill in the blank.

Which one of the following has an open circulatory system?

What does '$X$' represent in the given figure?

Which of the following does not take part in excretion in a cockroach?

Consider the following statements regarding cockroach and mark the correct option.
$(i)$ Head is formed by the fusion of $6$ segments.
$(ii)$ Mouth parts are biting and chewing type.
$(iii)$ Crop is the part of midgut.

The respiratory pigment in a cockroach is: