About how many times does the nymph of Periplaneta americana undergo moulting before becoming an adult ?

Options

A. (a) 4
B. (b) 2
C. (c) 17
D. (d) 13

Explanation

To solve the question of how many times the nymph of Periplaneta americana (the American cockroach) undergoes moulting before becoming an adult, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Organism**: Recognize that Periplaneta americana is the scientific name for the American cockroach.

2. **Understand the Life Cycle**: The cockroach undergoes a process called metamorphosis, which involves several stages of development from nymph to adult.

3. **Define Nymph**: The nymph is the juvenile form of the cockroach that resembles the adult but is smaller and not fully developed.

4. **Define Moulting**: Moulting, or ecdysis, is the process by which the nymph sheds its exoskeleton to grow. This is a crucial part of its development.

5. **Determine the Number of Moults**: Research indicates that the nymph of Periplaneta americana undergoes moulting approximately 13 times before it reaches the adult stage.

6. **Conclude the Answer**: Therefore, the nymph of Periplaneta americana undergoes moulting 13 times before becoming an adult.

### Final Answer:
The nymph of Periplaneta americana undergoes moulting **13 times** before becoming an adult. Thus, the correct option is **D**.

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