Endoskeletal structure present in the head is
(a) Apodeme
(b) Tentorium
(c) Fenestra
(d) Clypeus

Options

A. Apodeme
B. Tentorium
C. Fenestra
D. Clypeus

Answer

To solve the question regarding the endoskeletal structure present in the head, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for an endoskeletal structure located in the head. The term "endoskeletal" refers to structures that are internal to the body.

2. **Analyzing the Options**:
- (a) **Apodeme**: This is a term used for internal ridges or projections in arthropods that serve as muscle attachment sites, but it is not specifically an endoskeletal structure in the head.
- (b) **Tentorium**: This is a specific structure found in the head of arthropods, acting as a support framework. It is indeed an endoskeletal structure.
- (c) **Fenestra**: This term refers to openings or windows in a structure, not specifically an endoskeletal structure.
- (d) **Clypeus**: This is a part of the insect head, but it is not an endoskeletal structure; rather, it is an external feature.

3. **Identifying the Correct Answer**: Based on the definitions and functions of the terms, the Tentorium is the only option that fits the criteria of being an endoskeletal structure present in the head.

4. **Conclusion**: Therefore, the correct answer is **(b) Tentorium**.