Moulting of Second instar larva of Ascaris occurs in

Options

A. intestine
B. sand
C. blood vessels
D. lungs

Answer

To determine where the moulting of the second instar larva of Ascaris occurs, we can follow these steps:

### Step 1: Understanding the Life Cycle of Ascaris
Ascaris is a parasitic roundworm that infects humans. The life cycle begins when the eggs are ingested by a human host.

**Hint:** Consider the stages of the life cycle and where the larva develops after ingestion.

### Step 2: Entry into the Human Body
Once the infected eggs are ingested, they hatch in the small intestine, specifically in the duodenum. The larvae then penetrate the intestinal wall and enter the bloodstream.

**Hint:** Think about how the larva transitions from the intestine to other parts of the body.

### Step 3: Migration of the Larva
After entering the bloodstream, the larvae migrate through the body. They travel to various organs, including the lungs.

**Hint:** Identify the organs that are involved in the migration of the larvae after they leave the intestine.

### Step 4: Moulting Process
In the lungs, the larvae undergo moulting (a process where they shed their outer cuticle). This is essential for their growth and development into the next larval stage.

**Hint:** Recall the significance of moulting in the life cycle of parasites and where it typically occurs.

### Step 5: Conclusion
Based on the above steps, we conclude that the moulting of the second instar larva of Ascaris occurs in the lungs.

**Final Answer:** The moulting of the second instar larva of Ascaris occurs in the lungs.

---