When a human female reaches a certain age,then vaginal bleeding occurs for a few days after regular intervals of time :
What is this process known as in everday language ?

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about a biological process that occurs in human females at a certain age, characterized by vaginal bleeding at regular intervals.

2. **Identifying the Age**: This process typically begins during puberty, which for girls usually occurs between the ages of 12 to 14 years.

3. **Recognizing the Process**: The vaginal bleeding that occurs is a part of the menstrual cycle, which is a natural biological process.

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