How is the entry of only one sperm and not many ensured into an ovum during fertilisation in humans?

Explanation

To understand how the entry of only one sperm into an ovum is ensured during fertilization in humans, we can break down the process into several key steps:

### Step-by-Step Solution:

1. **Understanding the Structure of the Ovum and Sperm**:
- The ovum (egg) has an outer layer called the zona pellucida, which is crucial for fertilization. Inside the ovum, there is a nucleus and cytoplasm.
- The sperm consists of a head (which contains the nucleus and acrosome), a midpiece, and a tail.

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