Question

The first and last moults of Ascaris occur in which organ
A. Heart
B. Kidney
C. Liver
D. Intestine

Answer 1

Hint: Ascaris is a genus of parasitic nematode worms. The larvae undergo first moulting in the soil. Then the larvae undergo second and third moulting occurs in the lungs. Then, the fourth moulting occurs. The second stage larva goes from soil to lungs.

Complete answer:
Moulting, in many invertebrates, is called ecdysis, which is how an animal routinely casts off a part of its body. It occurs either at specific times of the year or at specific points in its life cycle.
In this process, the epidermis separates from the outermost cuticle. After that, the epidermis forms a protective layer around itself and then secretes chemicals that break down the insides of the old cuticle. This protective layer becomes part of the new cuticle. Muscular contractions and air intake cause the insect’s body to swell, thus splitting open the remains of the old cuticle, when the epidermis has formed the new cuticle. Finally, the new cuticle hardens. The bug squeezes out from the outgrown exoskeleton.
Larvae hatch from the eggs in your small intestine which is the first moult. Then penetrates the intestinal wall to travel to your lungs via your bloodstream or lymphatic system. The larvae break into your airway and travel up your throat, after maturing for about a week in your lungs where they're coughed up and swallowed.
Maturation- The parasites grow into male or female worms (last moult), once back in the intestines. Male worms are generally smaller and Female worms can be more than 15 inches long and a little less than a quarter-inch in diameter.
So, the correct answer is “Option D”.

Note:
Ascaris is nematode roundworms that reside like parasites in a human being’s small intestine. Human beings are infected by these worms when they consume food or water that is contaminated by Ascaris worm eggs. Larvae hatch from the eggs in your small intestine which is the first moult. The parasites grow into male or female worms (last moult), once back in the intestines.