In which group of animals is the larval form mostly similar to the adult?

Which of the following systems are not well-developed in $Aschelminthes$ (roundworms)?

The cross-section of an animal body is given below:
Which of the following animals will satisfy the above cross-section?

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

Female $Ascaris$ is differentiable from male in

Which of the following statements are correct about the life cycle of $Ascaris \; lumbricoides$?
$(A)$. Infective agent - Embryonated egg with $II$ Juvenile
$(B)$. Fertilised eggs containing the unsegmented ovum are passed with faeces
$(C)$. Four moultings of the larva occur: two outside in soil within the egg-shell, one in lungs and one in intestine
$(D)$. Site of location of worm - small intestine.