Fill in the following blanks with suitable words :
The features which help us to distinguish between a mature boy and a girl are called ………………… sexual characteristics.

Options

A. Primary
B. Secondary
C. Tertiary
D. Quaternary

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for a term that describes the features distinguishing a mature boy from a girl.

2. **Identifying Key Terms**: The key terms in the question are "mature boy," "girl," and "distinguish." This indicates that we are looking for characteristics that are evident during puberty.

3. **Types of Sexual Characteristics**: There are two types of sexual characteristics:
- Primary sexual characteristics: These are present at birth and include the reproductive organs.
- Secondary sexual characteristics: These develop during puberty and include features like breast development in girls and facial hair in boys.

4. **Focusing on the Right Characteristics**: Since the question specifies "features which help us to distinguish between a mature boy and a girl," we are looking for the secondary sexual characteristics, which are responsible for the physical differences that emerge during adolescence.

5. **Filling in the Blank**: Based on the understanding that we are looking for the features that develop during puberty, we can fill in the blank with the term "secondary."

Thus, the completed sentence is: "The features which help us to distinguish between a mature boy and a girl are called **secondary sexual characteristics**."

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