Question

A rhabditiform larva is formed in the life cycle of
A. Ascaris
B. Tapeworm
C. Hydra
D. Leucosolenia

Answer 1

Hint: Rhabditiform larvae is the characteristic of the nematodes. Splitting of the eggs of intestinal roundworm parasites releases rhabditiform larvae in the intestine where they reach the liver through the portal circulation, later they enter into the heart via pulmonary circulation and finally enter the lungs.

Complete answer:
Roundworm is the most common parasitic worm in humans.
They belong to the phylum Nematoda and family ascarididae.
In humans, it grows up to 30cm and it is responsible for the cause of a disease called ascariasis and helminthiasis.
It infects humans via the fecal-oral route.
When coming to the life cycle of the roundworm, the adult female produces the eggs, which we have commonly seen in feces, these eggs are not infective and the fertilized eggs are usually embryonated for 18 days in the soil, it this embryonated are ingested then in the body this eggs hatch and produce the Rhabditiform larvae, where this enters the intestine to the liver, and to heart, and finally to lungs.
As above said the rhabditiform larva belongs to Nematoda and Ascaris belongs to nematodes. So the correct answer is Ascaris.
Other given options are Tapeworm belongs to the family Cestoda, and the larva is cysticercus larva.
Hydra is the freshwater organism that belongs to the class hydrozoa and the larva of hydra is Planula.
The larva of Leucosolenia is called coeloblastula and it belongs to the Calcareous sponge.

So from the above examples, the answer is Nematoda.

Note:
To answer the above type of questions it’s good to prepare the list of all the worm names with their phylum and class and also the names of the larval form of those worms, it helps to gain marks without confusion.