Preparation of sperm before penetration of ovum is

Options

A. spermiation
B. cortical reaction
C. spermiogenesis
D. capacitation.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the preparation of sperm before it penetrates the ovum (egg). This process is crucial for successful fertilization.

2. **Role of Female Genital Secretions**: The secretions from the female genital tract play a significant role in preparing the sperm. These secretions help in removing certain substances that coat the sperm, particularly those on the acrosome.

3. **Acrosome Function**: The acrosome is a cap-like structure on the head of the sperm that contains enzymes necessary for penetrating the outer layers of the ovum. When the coating is removed, the receptor sites on the acrosome become exposed.

4. **Activation of Sperm**: Once the receptor sites are exposed, the sperm becomes activated and is ready to penetrate the egg. This activation is essential for the sperm to successfully fertilize the ovum.

5. **Terminology**: The process of sperm activation that occurs due to the removal of the coating is known as "capacitation." This term is specific to mammals and describes the changes that sperm undergo to gain the ability to fertilize an egg.

6. **Elimination of Other Options**:
- **Spermiation** refers to the release of sperm from the Sertoli cells in the testes.
- **Cortical Reaction** is a process that occurs in the egg after fertilization to prevent polyspermy (fertilization by multiple sperm).
- **Spermiogenesis** is the process of maturation of sperm cells.
- Therefore, the correct answer to the question is "capacitation."

**Final Answer**: The preparation of sperm before penetration of the ovum is known as capacitation.

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