10. Reaching the age of adolescence Class 8 Science [LATEST] Solutions Chapter Review in English - CBSE Study
NCERT Solutions for Class 8 Science are carefully prepared according to the latest CBSE syllabus and NCERT textbooks to help students understand every concept clearly. These solutions cover all important 10. Reaching the age of adolescence with detailed explanations and step-by-step answers for better exam preparation. Each Chapter Review is explained in simple language so that students can easily grasp the fundamentals and improve their academic performance. The study material is designed to support daily homework, revision practice, and final exam preparation for Class 8 students. With accurate answers, concept clarity, and structured content, these NCERT solutions help learners build confidence and score higher marks in their examinations. Whether you are revising a specific topic or preparing an entire chapter, this resource provides reliable and syllabus-based guidance for complete success in Science.
Class 8 English Medium Science All Chapters:
10. Reaching the age of adolescence
1. Chapter Review
Chapter Review:
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Growing up is a natural process. The period of life, when the body undergoes changes, leading to reproductive maturity, is called adolescence.
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The human body undergoes several changes during adolescence. These changes mark the onset of puberty.
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The period covers the ‘teens’ (13 to 18 or 19 years of age), adolescents are also called ‘teenagers’.
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Height depends on the genes inherited from parents.
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During puberty the secretion of sweat glands and sebaceous glands (oil glands) increases.
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Endocrine glands release hormones directly into the bloodstream. So, they are also termed ductless glands.
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In girls, breasts begin to develop at puberty and boys begin to grow facial hair, that is, moustaches and beard.
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The changes which occur at adolescence are controlled by
hormones. -
The male hormone is testosterone and the female
hormone is estrogen. -
Development of sexual organ as well as they produce sperm and ovum. In girls, breasts begin to develop at puberty and boys begin to grow facial hair, that is, moustaches and beard. Hair grows under the arms and in the region above the thighs or the pubic region.
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The ovary releases eggs for fertilization. If fertilisation does not occur, the released egg, and the thickened lining of the uterus along with its blood vessels are shed off. This causes bleeding in women which is called menstruation.
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Testes and ovary are even exocrine glands, which secrete sex hormone. These are responsible for secondary sexual characters so these are called sex hormones. The sex hormones are under the control of hormones from pituitary gland.
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The chromosomes which determine the sex in the human beings are called sex- chromosomes. These are two ane is ‘X’ and another ‘Y’. A female has two X chromosomes, while a male has one X and one Y chromosome.
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First The first menstrual flow begins at puberty and is termed menarch .
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At 45 to 50 years of age, the menstrual cycle stops. Stoppage of menstruation is termed menopause.
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The reproduction period in lady Starts in age of 10 – 12th years and ends in age of 40 – 45th .
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Endocrine glands release hormones into the bloodstream to reach a
particular body part called target site. -
The growing voice box in boys can be seen as a protruding part of the throat called Adam’s apple.
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Pituitary also secretes growth hormone which is necessary for the normal growth of a person.
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All human beings have 23 pairs of chromosomes in the nuclei of their cells.
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A female has two X chromosomes, while a male has one X and one Y chromosome.
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This change from larva to adult is called metamorphosis.
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Metamorphosis in insects is controlled by insect hormones. In a frog, it is controlled by thyroxine, the hormone produced by thyroid.
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A balanced diet means that the meals includs proteins,carbohydrates,fats and vitamins in requisite proportions.
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