NCERT Exemplar solutions for Science [English] Class 8 chapter 10 - Reaching the Age of Adolescence [Latest edition]

The belief that the mother is completely responsible for the sex of the child is wrong because the child

AIDS can spread from an infected person to another person through

Given below are events that lead to pregnancy and development of embryo.

1. Fertilization of egg
2. Maturation of egg
3. Release of egg
4. Embedding of embryo in thickened uterine wall.
   Which of the following options gives the correct order of sequence in which they occur?

For the metamorphosis of tadpoles which of the following elements must be available in water?

The most conspicuous visible change that occurs in boys during puberty is

Structures present in a cell which is responsible for determination of the sex of a baby is

Unscramble the underlined words in the following sentence.

Reproductive life of a woman lasts from hacreemn to spauoemen.

Unscramble the underlined word in the following sentence.

The development of a caterpillar to an adult butterfly is termed as poommertaissh.

Unscramble the underlined words in the following sentence.

The overgrowth of sumselc in xalnvr leads to the hoarse voice in adolescent boys.

Unscramble the underlined word in the following sentence.

Dannalier helps the body to adjust and fight the stress.

In females, the uterine wall thickens to receive the ______.

Endocrine glands release hormones directly into ______  for transportation to the ______.

The sex hormones, ______ and estrogen are responsible for the development of characters.

Release of sex hormones is under the control of a hormone secreted from the ______.

Give a suitable word for the following statement.

The site which responds to a hormone.

Give a suitable word for the following statement.

Name of a gland which transports secretions through ducts.

Give a suitable word for the following statement.

Chemicals which control changes at adolescence stage.

Give a suitable word for the following statement.

It marks the beginning of reproductive period.

Name the hormone that is released by testes at the onset of puberty.

Name the female hormone produced by ovaries that helps in development of mammary glands.

Match the hormones given in Column A with their deficiency disease given in Column B.

Lila always eats only dal and rice in every meal. She often falls ill and has become prone to diseases. Can you suggest changes in her diet which can make her healthy and free from disease?

Mention any two features of each that are seen in boys and girls which distinguish them from each other at puberty.

We should avoid taking medicines/drugs unless prescribed by a doctor. Give reasons.

A few of Paheli’s classmates eat potato chips and- burgers regularly during the recess in school. Are these healthy eating habits? Give reasons.

Read the statements given below and fill up the blanks with the correct words listed in the box.

1. The meal that includes all ______ is a balanced diet.
2. Insufficient production of ______ in the tadpoles leads to their incomplete development.
3. Endocrine glands are also called ______ glands.
4. After attaining puberty, boys develop a ______ voice.

Fill the blank circles in figure and identify the sex of child A and B. 

During adolescence, the body of boys and girls undergoes certain changes. Given below are few of those changes.

1. Broad shoulders
2. Wider chests
3. Wider region below waist
4. Development of muscles
5. Development of mammary glands
6. Growth of facial hair
7. Acne and pimples on face
8. Development of sex organs
9. High-pitched voice
10. Growth of pubic hair

Categorise these changes into those that occur in boys and those that occur in girls and fill in the table given below.

Body changes during adolescence.

In figure, mark the positions of the endocrine glands which release the hormones that

1. control the release of sex hormone
2. are responsible for the secondary sexual characters in boys.
3. prevent diabetes.
4. maintain the correct salt balance in the blood.

Given below are certain food items required for proper nourishment of adolescents. Name the nutrients present in the food items and write their functions.

Name the hormone which would be released during the following situations :

1. A frightened person.
2. Growth of a child to adult.
3. Development of caterpillar to moth.
4. Development of tadpole to frog.

In human females, each time during maturation and release of egg, the inner wall of uterus thickens. Is this thickening permanent? Give reasons.

John and Radha were classmates since childhood. When Radha became eleven years old, she developed a little swelling in her neck. She visited the doctor who started medication for her.
After a few years, John also developed a slight protrusion on his throat. He got worried and went to the doctor. But, the doctor assured him that it was a normal feature in boys while they are growing up. Can you think of any reasons for the difference in diagnoses?

Observe the chart and graph given in figure carefully and answer the following questions.

1. Which of the line represents the height of boys?
2. Which line represents the height of girls?
3. What is the difference between the pattern of increase in the height of boys and girls?
4. Is this pattern true for each individual?

Salma had a very soft and smooth skin during her childhood. As she entered adolescence, she developed pimples on her face. The skin specialist advised her to wash her face at regular intervals. Can you explain the reasons for the appearance of pimples on her face and suggest ways to prevent them?

Our government has legalised the age for marriage in boys and girls. Give reasons as why one should get married after a certain age?

It is believed that height of a child depends upon the genes inherited from parents. However, it is often seen that tall parents may have short . children and vice-versa. Are these factors other than genes that can cause these variations?