Reaching the Age of Adolescence NCERT Solutions Class 8 Science Chapter 10 with Answers

Reaching the Age of Adolescence NCERT Solutions Class 8 Science Chapter 10 with Answers

We have Provided the CBSE Solutions chapter-wise. Class 8 Science Chapter 10 Reaching the Age of Adolescence with Answers by expert subject teacher for latest syllabus and examination. Students can take a free CBSE Solutions of Reaching the Age of Adolescence. Each question has right answer Solved by Expert Teacher.

CBSE Solutions Class 8 Science Beehive Prose

Page No. 124

Exercise

Q1. What is the term used for secretions of endocrine glands responsible for changes taking place in the body?

Answer: Hormones are chemical substances which are secreted by endocrine glands. They are responsible for changes taking place in the body.

Q2. Define adolescence.

Answer: The time period which comes between the beginning of adulthood and puberty is called Adolescence. In this time period, the body undergoes different changes alongside reproductive maturity. It starts somewhat at the age of 11 and ends at the age of 18 or19. This period of adolescence may differ from person to person.

Q3. What is menstruation? Explain.

Answer: In females, the ova or eggs begin to mature with the onset of puberty (10 to 12 years of age) one egg get matured and is released by one of the ovaries once in about 28 to 30 days. During this period, the wall of the uterus becomes thick so as to receive the fertilized egg. In case it is fertilized, it begins to develop. This results in pregnancy. If the fertilization fails to take place, the ovum or the released egg and the thickened lining of the uterus along with its blood vessels are shed off. This causes bleeding in women. This is called menstruation. It occurs once in 28 to 30 days.

Q4. List changes in the body that take place at puberty.

Answer: Changes at puberty:

  • Increase in height.
  • Change in body shape.
  • Voice change. Changing the pharynx leads to a slight deepening of voice for girls and much deeper in boys.
  • Increased Activity of Sweat and Sebaceous Glands. The appearance of facial and pubic hair in boys, while the development of mammary glands in girls is observed.
  • Development of Sex Organs. Testis grows and starts producing mature sperms while ovaries start the menstrual cycle to produce eggs.
  • Reaching Mental, Intellectual and Emotional Maturity.

Q5. Prepare a table having two columns depicting names of endocrine glands and hormones secreted by them.

Answer:

Column AColumn B
Name of endocrine glands

(i) Testes
(ii) Ovaries

Pituitary glands

(iii) Thyroid
(iv) Adrenal glands
(v) Pancreas
Name of hormones

Testosterone (male)
Estrogen (female)

Sex hormones and brain hormones

Thyroxine
Adrenalin
Insulin

Q6. What are sex hormones? Why are they named so? State their function.

Answer: Sex hormones are the hormones that control the development of secondary sexual characteristics and also regulate the proper functioning of the sex organs. They are named so
because they are produced in both males and females by the respective sex organs under the influence of the pituitary gland.

Functions of sex hormones:

  • Testosterone: This hormone brings about secondary sex characters in boys such as the growth of a beard, the voice becoming hoarse, development of reproductive organs, etc.
  • Oestrogen: This hormone is responsible for the development of secondary sexual characters in females such as the enlargement of breasts, development of female reproductive organs, etc.

Q7. Choose the correct option.

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

(i) proper diet develops their brains.
(ii) 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.

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

(b) Reproductive age in women starts when their

(i) menstruation starts.
(ii) breasts start developing.
(iii) body weight increases.
(iv) height increases.

Answer: (i) menstruation starts.

(c) The right meal for adolescents consists of

(i) chips, noodles, coke.
(ii) chapatti, dal, vegetables.
(iii) rice, noodles and burger.
(iv) vegetable cutlets, chips and lemon drink.

Answer: (ii) chapatti, dal, vegetables.

Q8. Write notes on –

(a) Adam’s apple.

Answer: Adam’s apple: In human males, the larynx grows larger during puberty and can be seen as a protruding part of the throat. This protrusion is known as the Adam’s apple. In boys, under the influence of sex hormones, the larynx becomes prominent. As a result, the vocal cords become longer and thicker, causing the voice to become hoarse. However, in females, the larynx is of a small size and is hardly visible. Therefore, girls have a high pitched voice, while the voice of boys is low pitched.

(b) Secondary sexual characters.

Answer: Secondary Sexual Characters are the characters which distinguish a boy from a girl. the secondary sexual characters of boys include hair on chest, under the arms, growth of beard and moustaches while secondary sexual character of girls include development of breasts and growth of hair under the arms and pubic region. These characters are in control of the sex hormones.

(c) Sex determination in the unborn baby.

Answer: Secondary sexual characters: These are the characters which distinguish a male from a female are called secondary sexual characters. Some examples are given below:

  • In males, the growth of hair is seen on face and body.
  • Hair growth in the pubic region, under the arms, etc., is seen in both males and females.
  • In boys, voice becomes deeper.
  • Increase in weight.
  • Shoulders become broad and chest gets widened in males. The hips become wider in females.

Q9. Word game: Use the clues to work out the words.

Across

  1. Protruding voice box in boys
  2. Glands without ducts
  3. Endocrine gland attached to brain
  4. Secretion of endocrine glands
  5. Pancreatic hormone
  6. Female hormone

Down

  1. Male hormone
  2. Secretes thyroxin
  3. Another term for teenage
  4. Hormone reaches here through blood stream
  5. Voice box
  6. Term for changes at adolescence

Answer: 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

Q10. The table below shows the data on likely heights of boys and girls as they grow in age. Draw graphs showing height and age for both boys and girls on the same graph paper. What conclusions can be drawn from these graphs?

Answer: The graph depicts the relation between the age and height of both boys and girls. During puberty, there is a sudden increase in height of both boys and girls. On the basis of the above graph, it can be observed that during the age of 4-8 years, girls have less height as compared to boys. However, as soon as girls reach 12- 13 years, their height shows a sudden increase and becomes more than boys. In later years, growth in both sexes becomes stable. Growth during puberty is under the control of hormones.

We Think the given CBSE Solutions for class 8 Science book, Chapter 10 Reaching the Age of Adolescence with Answers Pdf free download will assist you. If you’ve got any queries regarding CBSE Class 8 Science Reaching the Age of Adolescence CBSE Solutions with Answers, drop a comment below and that we will come back to you soons.

Leave a Comment