Mark the odd one:

Options

A. Endometrium
B. Corpus Luteum
C. Acrosome
D. Graafian follicle

Answer

To solve the question "Mark the odd one" from the options provided (Endometrium, Corpus Luteum, Acrosome, Graafian Follicle), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Options**: The options given are:
- A. Endometrium
- B. Corpus Luteum
- C. Acrosome
- D. Graafian Follicle

2. **Understand Each Term**:
- **Endometrium**: This is the innermost layer of the uterus where implantation of the embryo occurs.
- **Corpus Luteum**: This is a structure that forms from the Graafian Follicle after ovulation and secretes hormones, primarily progesterone, to maintain the endometrium.
- **Acrosome**: This is a cap-like structure that covers the head of the sperm and contains enzymes necessary for penetrating the ovum.
- **Graafian Follicle**: This is a mature ovarian follicle that contains the developing oocyte (egg) and is involved in the ovulation process.

3. **Categorize the Terms**:
- Endometrium, Corpus Luteum, and Graafian Follicle are all components of the female reproductive system.
- Acrosome, on the other hand, is part of the male reproductive system related to sperm.

4. **Identify the Odd One Out**:
- Since Acrosome is associated with the male reproductive system, while the other three terms are related to the female reproductive system, Acrosome is the odd one out.

5. **Conclusion**: Therefore, the odd one among the options is **C. Acrosome**.