NCERT Solutions for Class 8 Science Chapter 10 Reaching The Age of Adolescence

Adolescence is an important stage in a person’s life that marks physical, emotional, and mental changes. It is the transition from childhood to adulthood and usually occurs between 12 to 20 years. Chapter 10 of Class 8 Science – Reaching the Age of Adolescence explains these changes, including puberty, hormonal balance, reproductive health, and sex determination.

Here we provide

 NCERT solutions for Class 8 Science Chapter 10 – Reaching the Age of Adolescence to help students understand key concepts and answer questions effectively.

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NCERT Solutions For Class 8 Science Chapter 10

Here we have provided NCERT Solutions for Class 8 Science Chapter 10 for the ease of students so that they can prepare better for their exams.

1. What is the term used for chemical secretions of endocrine glands responsible for changes taking place in the body?

Solution: Hormones are the chemical substances secreted by the endocrine glands. The changes occurring in the body are caused by hormones.

2. Define adolescence.

Solution: Adolescence is the time frame that spans from the start of adulthood until puberty. The body goes through several changes throughout this time in addition to reaching reproductive maturity. It finishes at the age of eighteen or nineteen, but it begins in some way at eleven. Adolescence can mean different things to different people.

Read More: NCERT Solutions for Class 8 Science Chapter 1

3. What is menstruation? Explain.

Solution: Menstruation is the term for the regular monthly process of the uterine lining being shed. It begins during adolescence and the female reproductive cycle. Every month, the uterus gets ready to receive a fertilized egg. As a result, the uterine lining thickens and receives blood flow to support the developing fetus. If the egg is not fertilized, the uterine lining degrades and leaks blood via the vagina. This takes place over two to eight days each month. The menstrual cycle is the name given to this monthly cycle.

4. List changes in the body that take place at puberty.

Solution: The following are the changes that occur throughout puberty: a) The body's weight and height will increase abruptly b) The legs, hands, face, and underarms tend to be the places where hair seems to grow. c) The ovary develops larger in females and begins to produce mature eggs; in contrast, the testis expands and begins to produce sperm in males. d) The shoulder widens and the chest expands in men, while the area below the waist expands in women. g) Excessive oil secretion from the skin appears to be the cause of acne. f) Hormones cause the larynx to become more noticeable in boys, and the vocal chord thickens and lengthens, giving them a gruff voice.

Read More: NCERT Solutions for Class 8 Science Chapter 2

5. Prepare a Table having two columns depicting the names of endocrine glands and hormones secreted by them.

Solution:

6. What are sex hormones? Why are they named so? State their function.

Solution: Sex hormones are the chemicals that are produced by the reproductive organs. For instance, the sex hormone generated by the ovary in females is known as oestrogen, while the sex hormone produced by the testis in males is known as testosterone. The following are a few tasks that the sex hormones carry out: Oestrogen: This hormone is in charge of the development of female reproductive organs and secondary sexual traits in females, such as breast augmentation. Testosterone: This hormone causes boys to develop secondary sex traits including growing facial hair, raspy voice, developing reproductive organs, etc.

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7. Choose the correct option.

(a) Adolescents should be careful about what they eat, because

(i) Proper diet develops their brains.

(ii) A proper diet is needed for the rapid growth taking place in their body.

(iii) adolescents feel hungry all the time.

(iv) Taste buds are well-developed in teenagers.

(b) Reproductive age in women starts when their

(i) menstruation starts.

(ii) breasts start developing.

(iii) body weight increases.

(iv) height increases.

(c) The right meal for adolescents consists of

(i) chips, noodles, coke.

(ii) chapati, dal, vegetables.

(iii) rice, noodles and burger.

(iv) vegetable cutlets, chips, and lemon drink.

Solution:

a) (ii) proper diet is needed for the rapid growth taking place in their body. b) (i) menstruation starts. c) (ii) chapati, dal, vegetables.

8. Write notes on—

(a) Adam’s apple.

(b) Secondary sexual characters.

(c) Sex determination in the unborn baby.

Solution:

a) Adam's apple: In male humans, the larynx enlarges during adolescence and appears as a portion of the throat that protrudes. We call this protrusion Adam's apple. The larynx becomes more noticeable in boys due to the influence of sex hormones. This results in a bigger and longer vocal cord, resulting in hoarseness of voice. In contrast, the larynx is tiny and barely noticeable in females. As a result, boys have a deep voice and girls have a high pitch.

b) Secondary sexual characteristics: Characters with secondary sexual features typically emerge during the puberty phase. These are the characteristics that contribute to the differences in the bodies of men and women.

Male characteristics include growing hair in the genital areas, chest breadth, beard look, and hoarseness of voice. Female characteristics include the onset of the menstrual cycle, breast growth, and genital hair growth.

c) Determining the sex of an unborn child: An unborn child's sex is determined by the pair of sex chromosomes that are present in its cells.

Human sex chromosomes are called X and Y chromosomes. Male sperm can have either the X or Y chromosome, although the X chromosome is always present in the ovum. The genetic composition of males consists of 44 autosomes plus one XY chromosome, whereas females have 44 autosomes plus one XX chromosome.

Read More: NCERT Solutions for Class 8 Science Chapter 3

9. Word game :

Use the clues to work out the words.

Across

3. Protruding voice box in boys

4. Glands without ducts

7. Endocrine gland attached to the brain

8. Secretion of endocrine glands

9. Pancreatic hormone

10. Female hormone

Down

1. Male hormone

2. Secretes thyroxine

3. Another term for teenage

5. Hormone reaches here through bloodstream

6. Voicebox

7. Term for changes in adolescence

Solution:

Across

1. Adam’s apple

2. Endocrine

3. Pituitary

4. Hormone

5. Insulin

6. Estrogen

Down

1. Testosterone

2. Thyroid

3. Adolescence

4. Target site

5. Larynx

6. Puberty

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Adolescence Meaning 

Adolescence is the period when a child's body develops into an adult's body, preparing for reproduction. The major change during this time is puberty, which leads to:

• Rapid growth in height and weight

• Development of secondary sexual characteristics

• Increased hormonal activity

• Emotional and psychological changes

Age of Puberty

• Girls: Between 8 to 14 years

• Boys: Between 9 to 16 years

These changes occur due to hormones, which are chemical messengers secreted by endocrine glands.

Characteristics of Hormones

Hormones play a crucial role in growth, metabolism, and reproduction. They are secreted by endocrine glands

• Travel through the bloodstream to target organs

• It works in small amounts but has powerful effects

• Can be harmful if unbalanced

• Are destroyed after their action

Feedback Mechanism

Hormones are controlled by a feedback mechanism. For example, if thyroid hormone levels are high, the pituitary gland stops producing thyroid-stimulating hormone (TSH) to maintain balance.

Changes During Puberty

1. Physical Changes

Increase in Height: Both boys and girls experience growth spurts.

Body Shape Changes:

• Boys develop broader shoulders and more muscles.

• Girls develop wider hips and breast growth.

Voice Changes:

• Boys experience a deepening voice due to enlarged vocal cords.

• Girls have a slight voice change.

Hair Growth: Facial, armpit, and pubic hair appear.

2. Emotional and Social Changes

• Adolescents may experience mood swings due to hormonal changes.

• Peer influence becomes stronger.

• Self-awareness and decision-making skills begin to develop.

Brain Development in Adolescence

The prefrontal cortex of the brain continues developing. This part controls decision-making, emotions, and reasoning.

• Teenagers may act impulsively or struggle with decision-making.

• Emotional changes are influenced by the limbic system.

Reproductive Health

Maintaining reproductive health is important for overall well-being. It includes:

• Personal hygiene (bathing, wearing clean clothes)

• Healthy eating (iron-rich foods, vitamins)

• Vaccination against infections like HPV

• Awareness about the menstrual cycle

The Menstrual Cycle in Girls

The menstrual cycle is a 28-day cycle where the uterus prepares for pregnancy. If fertilization does not happen, the uterus lining sheds, leading to menstruation.

Sex Determination in Humans

A baby's sex is determined at fertilization by chromosomes:

• Females have XX chromosomes.

• Males have XY chromosomes.

The father’s sperm determines the child’s sex, as sperms carry either an X or Y chromosome.

Metamorphosis in Animals

Metamorphosis is the process where an organism transforms from a larva into an adult.

Examples of Metamorphosis

Butterflies: Egg → Larva (Caterpillar) → Pupa → Adult

Frogs: Egg → Tadpole → Young Frog → Adult Frog

Methods to Control Overpopulation

Overpopulation affects resources, employment, and health services. Some control measures include:

• Educating young people about family planning

• Raising the marriage age to 18 for girls and 21 for boys

• Providing contraceptives and birth control methods

• Encouraging women's employment

• Community health programs

Sexually Transmitted Diseases (STDs)

STDs are infections spread through sexual contact.

Common STDs

• Gonorrhea – A bacterial infection affecting the reproductive organs

• Syphilis – Causes sores and nerve damage

• HIV/AIDS – Weakens the immune system

Prevention of STDs

• Use of protection (condoms)

• Avoiding multiple sexual partners

• Seeking proper medical care
  

Read More: NCERT Solutions for Class 8 Science Chapter 4

Class 8 Science Chapter 10 FAQs

1. What are some common sexually transmitted diseases (STDs)?

Common STDs include:

• Gonorrhea – Bacterial infection of the reproductive organs.

• Syphilis – Causes sores and nerve damage.

• HIV/AIDS – Weakens the immune system.

2. What is the menstrual cycle, and what are its phases?

The menstrual cycle is a 28-day cycle in which the uterus prepares for pregnancy. Its phases are:

• Menstrual Phase (Day 1-5): Shedding of the uterus lining.

• Follicular Phase (Day 6-14): Egg matures in the ovary.

• Ovulation (Day 14-16): A mature egg is released.

• Luteal Phase (Day 17-28): Uterus prepares for possible pregnancy.

3. How does the brain develop during adolescence?

The prefrontal cortex (responsible for decision-making and reasoning) continues to develop, and the limbic system (responsible for emotions) becomes more active, leading to mood swings and increased social awareness.

4. What are hormones, and how do they affect adolescence?

Hormones are chemical messengers secreted by endocrine glands. They regulate growth, metabolism, and reproductive functions during adolescence. Examples include testosterone in boys and estrogen in girls.