The infective stage of $Ascaris$ is:

Choose the correct option for characters of roundworm.
$(I)$ Body is circular in cross-section.
$(II)$ Parasite found in animals and plants.
$(III)$ Organ-system level of body organization.
$(IV)$ Incomplete digestive system.

The $Aschelminthes$ are commonly called roundworms because:

Male $Ascaris$ is differentiable from female $Ascaris$ in:

The excretory organ in the phylum Aschelminthes is:

In filarial worms $(Wuchereria \text{ } bancrofti)$, the males are ......... in length compared to the females.