NCERT Solutions for Class 8 Science Chapter 10
Important NCERT Questions
8th Chapter 10 Reaching the Age of Adolescence
NCERT Books for Session 2022-2023
CBSE Board and State Board
Questions No: 8 Part: b
Write notes on: Secondary sexual characters.
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Secondary sexual characters: Secondary Sexual Characters are those characters which distinguish a male from female. Some of the characters are as follows:
Boys
• Facial hairs such as beard and moustaches develop.
• Hair develops under the armpit, under chest and in the pubic regions.
• Voice becomes deeper.
• Muscles develop, and shoulder becomes broad.
• Increase in weight.
Girls:
• Development and enlargement of breasts.
• Hair develops under the armpit and in the pubic regions.
• Hips broaden and pelvic region widens.
• Initiation of menstrual cycle.
• Deposition of fat around hips.
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Secondary sexual characteristics are physical traits that emerge during puberty, marking the differentiation between males and females. These features are not directly linked to reproductive organs but are crucial for sexual distinction.
1. In Males:
– Facial and Body Hair: Development of facial (beard, mustache) and body hair (chest, arms).
– Voice Changes: Deepening of the voice due to the growth of the larynx (Adam’s apple).
– Muscle Development: Increase in muscle mass and broadening of shoulders.
– Genital Changes: Growth of the penis and testes.
2. In Females:
– Breast Development: Growth of breasts due to increased fat and glandular tissue.
– Body Shape: Wider hips and narrower waist.
– Pubic Hair: Growth of hair in the pubic area.
– Menstrual Cycle: Onset of menstruation, indicating reproductive readiness.
These characteristics arise from hormonal fluctuations, particularly androgens (e.g., testosterone in males) and estrogens (e.g., estradiol in females) released during puberty. While not directly involved in reproduction, they distinctly define gender and prepare the body for reproductive maturity.