Exoskeleton of each segment in cockroach consists of

Options

A. Dorsal tergum and a ventral sternum
B. Dorsal sternum and a ventral tergum
C. Sternum only
D. Tergum only

Explanation

To answer the question regarding the composition of the exoskeleton of each segment in a cockroach, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of the Cockroach**:
- The cockroach is an arthropod, which means it has an exoskeleton made of chitin. This exoskeleton provides protection and support.

2. **Identify the Components of the Exoskeleton**:
- The exoskeleton is segmented and consists of different parts. Each segment has plates that are arranged in a specific manner.

3. **Differentiate Between Dorsal and Ventral Parts**:
- The dorsal part of the exoskeleton is referred to as the "tergum," while the ventral part is known as the "sternum."

4. **Examine the Options Provided**:
- The options given are:
- A) Dorsal sternum and ventral sternum
- B) Dorsal sternum and ventral tergum
- C) Sternum only
- D) Tergum only

5. **Analyze Each Option**:
- Option A (Dorsal sternum and ventral sternum) is incorrect because there is no dorsal sternum.
- Option B (Dorsal sternum and ventral tergum) is also incorrect because it mixes up the terms.
- Option C (Sternum only) is incorrect as it does not account for the tergum.
- Option D (Tergum only) is incorrect as it does not account for the sternum.

6. **Conclusion**:
- The correct answer is that the exoskeleton of each segment in a cockroach consists of a dorsal tergum and a ventral sternum.

### Final Answer:
The exoskeleton of each segment in a cockroach consists of a dorsal tergum and a ventral sternum.