In an earthworm,which of the following acts as a hydrostatic skeleton?

If a transverse section of $Pheretima$ is cut through the $20^{th}$ segment,it contains:

Identify the correct terms for the following analogy:
$(i)$ Excretory organ in cockroach : Malpighian tubules :: In earthworm : ...........
(ii) Scientific name of cockroach : Periplaneta americana :: Scientific name of earthworm : ...........

In earthworms,smaller blood vessels deliver blood to the .....

The female genital aperture in earthworm is present ventrally on the segment: (in $^{th}$)

Which of the following cells in an Earthworm are responsible for excreting silicates consumed along with food?