Number of juvenile stages found during development of Ascaris

Options

A. 1
B. 2
C. 3
D. 4

Answer

To determine the number of juvenile stages found during the development of Ascaris, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Juvenile Stages**:
- Juvenile stages are the developmental phases of an organism before it reaches adulthood. In the case of Ascaris, we need to identify how many such stages occur before it becomes an adult.

2. **Life Cycle of Ascaris**:
- Ascaris is a nematode that primarily infects humans. The life cycle begins when a female Ascaris lays eggs in the human intestine.

3. **Egg Development**:
- The female Ascaris can lay around 200,000 eggs, which can be either fertilized or unfertilized. The fertilized eggs are released into the environment through feces.

4. **Juvenile Stage Formation**:
- Once the fertilized eggs reach the soil, they develop into the first juvenile stage (larva) after about 10 to 14 days. This larva is known as the "rhabditiform larva" and is not yet infective.

5. **First Molting**:
- After about a week, the first juvenile stage undergoes its first molting, transforming into the second rhabditiform larva. This second stage is infective.

6. **Migration and Further Development**:
- The infective second juvenile stage enters the human body through contaminated food or water and migrates through the intestines to the lungs, where it undergoes further molting.

7. **Second and Third Juvenile Stages**:
- In the lungs, the larva undergoes second and third molting, resulting in the formation of the third juvenile stage.

8. **Final Molting**:
- The larva then migrates back to the intestine, where it undergoes a final molting (fourth molting) to reach sexual maturity, thus becoming an adult Ascaris.

9. **Total Count of Juvenile Stages**:
- In total, there are four juvenile stages formed during the life cycle of Ascaris:
- First juvenile stage (rhabditiform larva)
- Second juvenile stage (infective rhabditiform larva)
- Third juvenile stage (after molting in the lungs)
- Fourth juvenile stage (after final molting in the intestine)

### Conclusion:
The total number of juvenile stages found during the development of Ascaris is **4**.