KSEEB Solutions For Class 8 Science Chapter 13 Reaching The Age of Adolescence

KSEEB Solutions for Class 8 Science Chapter 13 Reaching The Age of Adolescence Points To Remember

Humans become capable of reproduction after puberty sets in. Between the ages of 11 years and 19 years, children are called adolescents.
Puberty: It is the time when sex organs begin to work. The onset of puberty starts much earlier in girls, between 8 and 13 years of age, whereas it starts between 10 and 14 years of age in boys and lasts up to 2 to 4 years
Changes during Puberty:
1. Increase in Height: The bones of the eggs and arms elongate and the individual becomes tall and lanky.
2. Changes in Body Shape: In boys, the body becomes more muscular, and the shoulder becomes wider. In girls, the body shows curves in certain parts, and the region below the waist becomes wider and broader
3. Change in Voice: In boys, the voice becomes hoarse and heavy due to the extra growth of the larynx (voice box). In girls, the voice becomes high-pitched and shriller
4. Sweat and sebaceous glands: They become more active and secrete more sweat and oil. Pimples or acne appear due to the increased action of sebaceous glands or oil glands.
5. Emotional aspects develop.
6. Mental and intellectual development is at its peak.
7. The sex organs grow and become functionally active. The testis starts producing male gametes, called sperms. The ovaries grow and release one mature ovum in a periodic cycle of 28 days.
The onset of puberty and the maturity of reproductive parts are controlled by hormones.
Hormones are secretions of endocrine glands which pour them directly into the bloodstream.
The pituitary gland secretes hormones which include growth hormones and hormones that make other glands such as the testes, ovaries, thyroids, and adrenal, secret hormones. The pancreas secretesnsuinm, and the thyroid produces adrenalin.
Testosterone is the male hormone and estrogen, is the female hormone. The uterine wall in females The uterine wall in females prepares itself to receive the developing fertilised egg.
In case there is no fertilisation, the thickened lining of the uterine wall breaks down and goes out of the body along with blood. This is called menstruation.
SpermandOvum fuses together to form a zygote. Sex chromosomes in sperm determine the baby’s gender.
Humans have 23 pairs of chromosomes in each cell pair of chromosome forms the sex chromosomes.
Males carry XY and females carry XX chromosomes. If a sperm carrying X fertilises the ovum with X chromosome, then the resulting baby is a girl.
If a sperm carrying a Y chromosome fertilises the ovum with X chromosome, then the resulting baby is a boy. Hence, males are responsible for the gender of newly formed babies.

Reproductive Health:
1. It is important to eat balanced food and maintain personal hygiene during adolescence. Cleaning of private parts is important to prevent possible infections.
2. The activity of sweat glands increases in puberty and releases bad odor from the body frequent bathing is necessary.
3. Physical exercise keeps the body fit and healthy as it releases a lot of sweat.
4. Peer pressure is best addressed by selfconfidence and a healthy lifestyle.

KSEEB Solutions For Class 8 Science Chapter 13 Reaching The Age Of Adolescence

KSEEB Solutions For Class 8 Science Chapter 13 Reaching The Age Of Adolescence PDF

Reaching The Age of Adolescence NCERT Textbook Exercises

Question 1. What is the term used for secretions of endocrine glands responsible for changes taking place in the body?
Answer: The term used for the secretion of endocrine glands is hormones, which are responsible for various changes taking place in the body.

Question 2. Define adolescence.
Answer: The period of life when the body undergoes changes: leading to reproductive maturity, is called adolescence.

Question 3. What is menstruation? Explain.
Answer: The cyclic flow of blood and mucus along with the inner lining of the uterus in case of no fertilisation of the egg from the female body is called menstruation. Each month uterus prepares itself to receive the fertilized egg. If fertilisation does not occur the immer Imaging breaks away and comes out through the vagina for 3-5 days.

Question 4. List changes in the body that take place at puberty.
Answer: The onset of puberty brings about:
1. Growth of the reproductive organs which begin to function.
2. Hair growth at various places of the body. Breasts develop in girls and facial hairs appear in boys.
3. Voice of the boys becomes hoarse as the voice box enlarges during adolescence.

Question 5. Prepare a table having two columns depicting the names of endocrine glands and hormones secreted by them.
Answer:
reaching the age of adolsense depicting names table

Karnataka Board Class 8 Science Chapter 13 Solutions

Question 6. What are sex hormones? Why are they named so? State their [function.
Answer: Testes and ovaries secrete sex hormones. This is secreted by endocrine glands, These hormones are responsible for the male and female secondary sexual characteristics. That is why these hormones are called sex- hormones. Further, the sex-hormone are under the control of hormones from pituitary glands.

Question 7. Choose the correct option.

Adolescents should be careful about what they eat, because
1. Proper diet develops their brains.
2. Proper diet is needed for the rapid growth taking place in their body.
3. Adolescents feel hungry all the time.
4. Taste buds are well-developed in teenagers.

Reproductive age in women starts when their
1. Menstruation start.
2. Breast start developing
3. Body weight increases
4. Height increases.

The right meal for adolescents consists of
1. Chips, noodles, coke.
2. Chapatti. dal vegetables.
3. Rice, noodles, and burger.
4. Vegetable cutlets, chips, and lemon drink.

Answer:
Adolescents should be careful about what they eat: 2. Proper diet is needed for the rapid growth taking place in their bodies.
Reproductive age in women starts when their: 1. Mensuration starts.
The right meal for adolescents consists of 2. Chapatti, dal, and vegetables.

KSEEB Class 8 Science Solutions for Reaching The Age Of Adolescence

Question 8. Write notes on
1. Adam’s apple.
2. Secondary sexual characters.
3. Sex determination in the unborn babies.

Answer:
1. Adam’s apple: At puberty, the voice box or the larynx begins to grow. The growing voice box in boys can be seen as a protruding part of the throat called the Adam’s apple.
2. Secondary sexual characters: Those changes that take place at puberty in boys and girls are called secondary sexual characters. It includes an increase in the size of breasts in girls and pubic hairs around genital organs in girls. In boys, facial hair and cracking of voice are secondary sexual
features.
3. Sex determination in the unborn baby: Human beings have 23 pairs of chromosomes. One pair of male (XY) and one pair of chromosomes in female (XX) are called sex chromosomes. When the sperm containing the Y chromosome fuse with the egg the sex of the baby is male and when the X chromosome containing the sperm fertilize the egg the sex of the baby is female.

Question 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 brain
8. Secretion of endocrine glands
9. Pancreatic hormone
10. Female hormone
Down
1. Male hormone
2. Secretes thyroxin
3. Another term for teenage
5. Hormone reaches here through the bloodstream
6. Voicebox
7. Term for changes in adolescence

Answer:
ACROSS DOWN
3. ADAMS APPLE 1. TESTOSTERONE
4. ENDOCRINE 2.THYROID
7. PITUITARY 3. ADOLESCENCE
8. HORMONE 5. TARGET SITE
9. INSULIN 6. LARYNX
10. ESTROGEN 7.PUBERTY

Reaching The Age Of Adolescence Class 8 KSEEB Solutions With Answers

Question 10. The table below shows the data on the likely height of boys and girls as they grow in age. Draw graphs showing the height and age of both boys and girls on the same graph paper. What conclusions can be drawn from these
reaching the age of adolesense height of boys and girls table
Answer:

Reaching The Age of Adolescence Activities

Question 1. Collect information from magazines or from doctors and prepare a note on the importance of consuming iodized salt. You can also look for this information on the internet.
Answer: Iodine is necessary for the thyroid gland to produce thyroxine hormone. It regulates the metabolism of carbohydrates, fats, and proteins, so as to produce the best balance for growth. A deficiency of iodine in our diet leads to a reduction in the formation of thyroxine hormone causing goiter disease.

Question 2. Get ideas from the pictures given Prepare charts or posters and paste them into the class so that you are aware of the diet for adolescents. You may use your creative ideas and present them as an advertisement. You may even organise a competition on this topic.

Answer: You have already studied about food and its components and you are aware of the importance of various ingredients of food like vitamins, proteins, carbohydrates, fats, minerals, water, etc. So you can do this activity yourself.

Reaching The Age Of Adolescence Class 8 KSEEB Questions And Answers

Question 3. Collect data on the number of children in your class who exercise regularly and who do not exercise regularly. Did you notice any difference in their fitness and health? Prepare a report on the benefits of regular exercise.
Answer:
Doing exercises daily keeps one fit and healthy. It is a popular saying that a sound mind resides in a sound body, i.e., if you are healthy or physically fit, you are mentally sound also.
You can collect data on the number of children in your class who exercise regularly and who do not. You will notice the difference clearly in their fitness and health. Also, prepare a note on the benefits of regular exercise.

Reaching The Age of Adolescence Additional Questions

Question 1. What is Adam’s apple?
Answer: The protruding part of the throat in males is called Adam’s apple.

Question 2. Name the hormone in females that is produced by ovaries and helps in the development of mammary glands.
Answer: Estrogen

Question 3. Whose height grows faster initially – boys or girls?
Answer: Girls

Question 4. Name a gland that transports secretions through ducts.
Answer: Sweat glands/salivary glands/oil glands (anyone).

Question 5. What are hormones?
Answer: The chemical substances produced by endocrine glands are called hormones.

KSEEB Class 8 Science Reaching The Age Of Adolescence Exercise Solutions

Question 6. What is menarche?
Answer: The first menstrual flow begins at puberty and is termed menarche.

Question 7. Name the chromosome present in a female.
Answer: Chromosome

Question 8. What is a vital change which marks puberty in boys and girls?
Answer: During puberty, the human body undergoes several changes, but the most important change which marks puberty is that boys and girls become capable of reproduction.

Question 9. Why do boys have a hoarse voice at puberty?
Answer: The voice box or larynx begins to grow at the onset of puberty. This growing voice box in boys can be seen as a protruding part of the throat called Adam’s apple. This leads to the voice becoming hoarse.

Question 10. Why are endocrine glands also called ductless glands?
Answer: Endocrine glands release hormones directly into the bloodstream. So, they are termed ductless glands. For example, pituitary, and thyroid) pancreas, etc.

Question 11. What are secondary sexual characters?
Answer: At puberty, in girls, breasts begin to develop, the region below the waist becomes wider, the voice becomes shriller. Boys begin to grow facial hair, i.e., mustache and beard. Boys also develop hair on their chest, the muscles of the body grow more prominently, and develop a larger voice box which can be seen as a protruding part of the throat called Adam’s apple. In both boys and girls, hair grows under the arms and in the pubic region. As these features distinguish the male from the female they are called secondary sexual characters.

Question 12. What are sex hormones? How do they work in the human body?
Answer:
1. Sex hormones help boys and girls develop sex organs to enable them for reproducing. These hormones lead them to reproductive maturity.
2. In girls, estrogen makes the breasts develop. Milk-secreting glands or mammary glands develop inside the breasts. Ovaries begin to produce eggs.
3. In boys, testosterone is released by the testes. Testes begin to release sperms. Changes in boys are also seen due to this hormone.

Question 13. Explain the terms menarche and menopause.
Answer: The first menstrual flow begins at puberty and is termed as menarche. At 45 to 50 years of age, the menstrual cycle stops. Stoppage of menstruation is called menopause.

Question 14. What do you mean by reproductive health?
Answer: The physical and mental well-being of an individual is regarded as an individual’s health.
1. To keep the body healthy, every human being, at any age,needs to have a balanced diet.
2. The person must also observe personal hygiene and undertake adequate physical exercise.
3. Thus, reproductive health refers to the diseases, disorders, and conditions that affect the functioning of the male and female reproductive system during all stages of life.

Explanation Of Reaching The Age Of Adolescence In KSEEB Science

Question 15. What is the role of hormones in completing the life history of insects and frogs?
Answer:
1. Hormones play an important role in the completion of the life cycle of insects and frogs.
2. Metamorphosis in insects is controlled by insect hormones. In a frog, it is controlled by thyroxine, the hormone produced by thyroid gland.
3. Thyroxine production requires the presence of iodine in water. In the water in which iodine is not, present, the tadpoles cannot become adults.

Reaching The Age of Adolescence Multiple Choice Questions

Question 1. The belief that the mother is completely responsible for the sex of the child is wrong because the child
1. Gets sex chromosomes only from the mother.
2. Develops in the body of the mother.
3. Gets one sex chromosome from the mother and the other from the father.
4. Gets sex chromosomes only from the father.

Answer: 3. Gets one sex chromosome from the mother and the other from the father.
Explanation: Mother has a pair of the X chromosome on their 23“ chromosome set and she always donates the X chromosome to the offspring. Father has an XY chromosome on the 23rd set. If the father donates the X chromosome, the child will be female. If Father donates the Y chromosome then the child will be male. Hence it is the father who is responsible for the sex of the child.

Question 2. AIDS can spread from an infected person to another person through:
1. Sharing food
2. Blood transfusion
3. Sharing comb
4. A mosquito bite

Answer: 2. Blood transfusion
Explanation: AIDS can be transmitted from an infected person by the following means:
1. Sharing needles and syringes
2. From infected mother to fetus.
3. By sexual means through the exchange of fluids.
4. From infected mother to a baby through breast milk.

Karnataka Board 8th Science Chapter 13 Important Questions And Answers

Question 3. Given below are events that lead to pregnancy and development of the embryo.
1. Fertilization of the egg
2. Maturation of egg
3. Release of egg
4. Embedding of the embryo in the thickened uterine wall.

Answer:
2. Maturation of egg
3. Release of egg
1. Fertilization of egg
4. Embedding of the embryo in the thickened uterine wall.
Explanation: The sequence of events is as follows:
1. Maturation of egg after puberty.
2. Release of the egg cell.
3. Fertilization of the egg by sperm to form the zygote.
4. Repeated division of zygote to form an embryo.
5. Embryo gets embedded in the wall of the uterus for further development.

Step-By-Step Solutions For Reaching The Age Of Adolescence Class 8 Karnataka Board

Question 4. For the metamorphosis of tadpoles which of the following elements must be available in the water?
1. Chlorine
2. Carbon
3. Sulphur
4. Iodine

Answer: 4. Iodine
Explanation: Metamorphosis is brought by a hormone called thyroxine. The thyroid gland needs Iodine to secrete Thyroxine. Hence Iodine should be present in water for the metamorphosis of tadpoles.

Question 5. The most conspicuous visible change that occurs in boys during puberty is:
1. Development in the voice box.
2. Increase in height.
3. Production of sperm.
4. Increased sweating.

Answer: 2. Increase in height.
Explanation: Most conspicuous change during puberty is the sudden increase in height. At this time the long bones, that is, the bones of the arms and the legs elongate and make a person tall.

KSEEB Class 8 Science Chapter 13 Important Questions

Question 6. Structures present in a cell which is responsible for determination of the sex of a baby is
1. Cytoplasm
2. Cell membrane
3. Nucleus
4. Chromosome

Answer: 4. Chromosome
Explanation: 23″ set of the chromosome which is called a sex chromosome determines the sex of the child. If the 23″ set of the chromosomes is XX baby will be female and if the sex chromosome is XY then the baby will be a boy.

KSEEB 8th Standard Science Chapter 13 Notes And Solutions

Question 7. Unscramble the underlined words in the following sentences.
1. Reproductive life of a woman lasts from hacreemn to spauoemen.
2. The development of a caterpillar into an adult butterfly is termed as poommertaish.
3. The overgrowth of sumsele in xalnyr leads to the hoarse voice in adolescent boys.
4. Dannalier helps the body to adjust and fight stress.

Answer:
1. Menarche, Menopause
2. Metamorphosis
3. Muscles, larynx
4. Adrenalin

Question 8. Complete the following sentences.
1. In females, the uterine wall thickens to receive the________.
2. Endocrine glands release hormones directly into _______ for transportation to the______.
3. The sex hormones, and estrogen are responsible for the development of _______ characters.
4. Release of sex hormones is under the control of a hormone secreted from the______.

Answer:
1. In females, the uterine wall thickens to receive the fertilized egg.
2. Endocrine glands release hormones directly into the bloodstream for transportation to the target site.
3. The sex hormones, Testosterone, estrogen, and estrogen are responsible for the development of secondary sexual characteristics.
4. Release of sex hormones is under the control of a hormone secreted from the pituitary gland.

Question 9. Give a suitable word for each of the following statements.
1. The site which response to a hormone.
2. Name of a gland which transports secretions through ducts.
3. Chemicals which control changes at the adolescence stage.
4. It marks the beginning of the reproductive period.

Answer:
1. Target site
2. Sweat glands/salivary glands/oil glands (anyone)
3. Hormones
4. Puberty

KSEEB Class 8 Science Chapter 13 Textbook Solutions

Question 10. Name the hormone that is released by testes at the onset of puberty.
Answer: Testosterone is the hormone that is released by testes at the onset of puberty

Question 11. Name the female hormone produced by ovaries that helps in the development of mammary glands
Answer: Estrogen is the female hormone produced by ovaries that helps in the development of mammary glands.

Question 12. Match the hormones given in Column A with their deficiency disease given in
Column A Column B
Thyroxine 1. Salt imbalance
Growth hormone 2. Diabetes
Insulin 3. Goiter
Adrenal hormone 4. Dwarfism
Answer:
Column A Column B
Thyroxine 1. Salt imbalance
Growth hormone 4. Dwarfism
Insulin 2. Diabetes
Adrenal hormone 1. Salt imbalance

Question 13. Lila always eats only dal and rice at every meal. She often falls ill and has become prone to diseases. Can you suggest changes in her diet that can make her healthy and free from disease?
Answer: Food Lila takes every day consists of only carbohydrates and proteins. To be free from disease Lila should eat food with vitamins and minerals. She should include more vegetables and fruits in her daily diet.

Question 14. Mention any two features each that are seen in boys and girls each to distinguish them from each other at puberty.
Answer: Two features seen in boys at puberty are:
1. Growth of facial hairs
2. The voice becomes hoarse.
Two features seen in girls at puberty are:
1. Breast development.
2. The region below the waist becomes wider.

Detailed Notes On Reaching the Age Of Adolescence KSEEB

Question 15. We should avoid taking medicines/drugs unless prescribed by a doctor. Give reasons.
Answer: We should not take medicines/drugs unless prescribed by a doctor because some medicines have various side effects which may also lead to adverse effects or can get addicted to drugs, which ruin our health and happiness.

Question 16. A few of Paheli’s classmates eat potato chips and burgers regularly during recess at school. Are they healthy eating habits? Give reasons.
Answer: No. Potato chips and burgers are not healthy as it contains very little nutritional value in them and is not good foods to eat regularly.
Flow Chart

Reaching The Age Of Adolescence Adolescence

KSEEB Solutions For Class 8 Science Chapter 13 Reaching The Age of Adolescence