Important Questions Class 8 Science Chapter 10

Important Questions Class 8 Science Chapter 10- Reaching the Age of Adolescence

Chapter 10 of the CBSE Class 8 Science syllabus is about ‘Reaching the Age of Adolescence’. Adolescence is the period of transition in one’s life when the body undergoes certain changes leading to reproductive maturity. The (WHO) World Health Organisation defines adolescence as a period between eleven and eighteen years. Hence, adolescence takes place between childhood and adulthood. The human body undergoes various changes during adolescence. These different changes mark the onset of puberty. Puberty is a phase wherein the reproductive organs of a human body become functionally active. Puberty ends when adolescents reach reproductive maturity.

Important Questions Class 8 Science Chapter 10 provides students with solutions to various essential questions that cover the majority of the topics discussed in the chapter. The students get a vivid description of the chapter, which helps them learn more about the process of adolescence, what it means, and what changes occur at this age. The stepwise solutions will help students prepare for their examinations, broadly covering all the aspects included in the chapter.

Our question bank of Class 8 Science Chapter 10 Important Questions helps students to score well academically and comprehend all the concepts in the chapters. The Science faculty at Extramarks has curated a set of Important Questions Class 8 Science Chapter 10, which helps students take multiple revisions and clear doubts regarding the chapter.  Extramarks has compiled various practise and study materials like NCERT solutions,NCERT books, CBSE revision notes, and CBSE sample papers. To get the maximum benefit, students can browse through these questions of Science Class 8 Chapter 10 Important Questions and practise them on a regular basis on the Extramarks website.

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Important Questions Class 8 Science Chapter 10 – With Solutions

The Extramarks team has compiled a complete set of Important Questions Class 8 Science Chapter 10 for all the students to help them progress academically. These questions have been curated carefully per the CBSE syllabus and NCERT guidelines. These questions help students to generate an understanding of the exam question pattern, and accordingly prepare for their exams. Science Class 8 Chapter 10 Important Questions are solutions to various questions, including MCQs, short answers, long answers, etc. By registering on the Extramarks website, students can access all these materials.

The list provided below consists of a few questions and their solutions from our Important Questions Class 8 Science Chapter 10.

Question 1. The reproductive phase of a woman lies between her _____ and menopause.

1. menstrual cycle
2. menstruation
3. menarche
4. ovulation

Answer 1:

Solution

The correct option is (C) menarche.

The reproductive phase of a woman starts with her first period(menarche) at around 11-14 years of age. And it stops when menstrual cycles permanently cease due to the natural depletion of ovarian oocytes from ageing (48-50 years). This is called menopause. Hence, the reproductive phase of women generally lies between their menarche and menopause.

Question 2. We should avoid taking medicines/drugs unless prescribed by the doctor. Give reasons.

Answer 2:

A doctor’s prescription is a must before we proceed to take medicines and drugs because:

1.The general public is unaware of the scope of medicine, that is, the drug’s reach and efficacy against pathogens.. Besides, we are not trained to compute the exact dosage of the drug. Just as overdose leads to side effects, under dosage also leads to the pathogens developing a resistant strain to the antibiotic, making it ineffective in the long run.

2.Self-medication can become addictive and cause irreparable damage to our bodies.

Question 3. John and Radha have been classmates since childhood. When Radha was eleven years old, she developed a little swelling on her neck. Radha visited the doctor, who started the medication. After a few years, John also seemed to develop a slight protrusion on his throat. He got worried and went to the doctor.  But, the doctor assured him it was normal for boys to grow up with this. Can you think of any reason for the difference in diagnosis?

Answer 3:

The swelling in Radha’s neck may have been because of goitre, an enlargement of the thyroid gland when it produces an insufficient quantity of thyroxine. However, the protrusion in John’s throat would result from the growth of the voice box in adolescent boys. It is called Adam’s apple.

The difference in diagnoses is because of this reason.

Question 4. How is the sex of the child determined in human beings?

Answer 4:

Sex determination of human beings:

1. The sex of a child in humans is determined by the type of male gamete (i.e. X and Y chromosomes) that fertilises with the female gamete (i.e. X and X chromosomes).
2. There are a total of 23 pairs of chromosomes in each mother and father, 22 of which are Autosomes, and only one pair, the 23rd, is the sex chromosome, which actively participates in the process of sex determination.
3. Males and females have two sets of sex chromosomes; a male (XY) has one X and one Y sex chromosome, whereas a female (XX) has both X sex chromosomes, one of which is active.
4. During fertilisation, sperm fertilises the egg cell, resulting in the formation of a zygote.
5. If X-chromosome sperm fertilises an X-chromosome ovum, the child will be a girl (XX), whereas Y-chromosome sperm fertilises an X-chromosome ovum, and the child will be a boy (XY).

Question 5. What is the necessity of a balanced diet for adolescents?

Answer 5:

Balanced diet:

1. A balanced diet can be defined as a diet that contains all the necessary components in adequate amounts to provide nutrition to our body.
2. It includes protein, carbohydrates, vitamins, minerals, and healthy fats.

Adolescents:

1. Individuals in the age group of 10 to 19 years are called adolescents.
2. This period of transition between childhood and adulthood is called adolescence.
3. During the adolescence period, individuals develop both mentally and physically.
4. For proper growth and development, an adolescent should have a balanced diet.

Question 6. Which of the following will not have HIV?

1. Blood
2. Sweat
3. Semen
4. Breast milk

Answer 6:

The correct option is B. Sweat

Blood, semen, and breast milk are all our body’s internal fluids. Once the virus enters the body, it begins dividing and spreading all over the body. It is present in internal fluids like blood and is transmitted to healthy individuals only through the exchange of these body fluids.HIV does not spread through sweat.

Question 7. Write a short note on the reproduction phase in humans.

Answer 7:

 In both girls and boys, the onset of the reproductive phase is indicated by adolescence and commences with the development of various secondary sexual characteristics. Reproduction may occur once the gonads start producing gametes. They include ovum in females and sperm in males. In both males and females, the reproductive stage commences at Puberty. The reproductive stage in females ceases after 50 years; in males, however, the reproductive stage lasts for life. In girls, Puberty is usually marked by the onset of the Menstrual cycle or menstruation . The reproductive phase in girls is observed from the age of 10 to 15, when Puberty is attained. At this particular stage, the eggs in the ovaries start to mature. A mature ovum is then released from one of the two ovaries every 28 – 30 days. This process is known as ovulation. The lining of the uterus turns thicker and readies itself to implant. Fertilisation occurs if the sperm unites with the egg, leading to pregnancy. In the event of no fertilisation, the lining of the uterus sheds, which leads to bleeding and, hence, menstruation. The first menstrual flow is called menarche. The menstrual cycle in women ceases after 50 years and is referred to as menopause. The menstrual cycle stops forever after menopause. The time interval between one menstrual cycle and the next may vary from 28 to 30 days. This stage in women results from a few hormones and various sex hormones. Fluctuations in levels of these hormones may alter the ovulation day. Hormonal imbalance may lead to irregular menses.

Question 8. Our government has legalised the age of marriage for boys and girls. Give some reasons as to why one should get married after a certain age.

Answer 8:

Marriage after legal age:

1. An individual becomes mature mentally and sexually after a certain age.
2. The Indian government believes that people should marry after reaching this maturity level.
3. In India, the legal age of marriage for boys is 21, and for girls, it is 18.
4. Early marriage and parenthood can hamper the career of an individual.
5. It can cause financial problems and health problems as well.
6. A person may not be ready for such responsibilities in adulthood.

Question 9. A child’s height depends on the genes inherited from parents. However, it is seen that tall parents may have short children and vice-versa. Are there factors other than genes that may cause these variations?

Answer 9:

Nutrition:

1. Nutrition and height development are closely connected. It needs sufficient energy, amino acids, water, lipids, vitamins, and minerals for cells to divide and develop. People get roughly 50 necessary nutrients for growth from eating.
2. The main reasons for growth failure, particularly in youngsters whose rapid development rate, is insufficient food intake or food with insufficient calories.
3. Although a child’s height is determined by genes they receive from their parents, other factors can also affect a child’s height. These include hormones, diseases, a healthy diet, and exercise.
4. As different nutrients aid in forming bones, muscles, tissues, and other body parts, if a child is not receiving the right nutrients from his diet, it will impact his growth and development.
5. Like dwarfism, excessive growth or gigantism in children may result from the pituitary gland’s improper secretion of growth hormone.
6. Proper and consistent exercise is necessary to develop strong, healthy bones, and muscles.
7. Additionally, some illnesses result in the body’s incorrect growth and development. So these elements affect a person’s height.

Question 10. Mention any two features seen in boys and girls to distinguish them from each other at Puberty.

Answer 10.

Two features that are noticed in boys during Puberty are

1. Growth of facial hair
2. The voice starts becoming hoarse.

Two features noticed in girls at Puberty are

1. Development of breasts.
2. The region below the waist becomes wider.

Question 11. Name the hormone which would be released in the following situations:

1. a frightened person.
2. growth of a child into an adult.
3. development of the caterpillar into a moth.

• tadpole to frog development.

Answer 11:

(1) Adrenaline: When a person is scared, the adrenaline hormone is released.

(2) Growth hormone is responsible for a child’s growth into adulthood.

(3) Insect hormones: insect hormones are responsible for the caterpillar to moth development.

(4) Thyroxine—It is responsible for developing tadpoles into frogs.

Question 13. In human females, the uterus’s inner wall thickens during the egg’s maturation and release. Is this thickening permanent? Give reasons.

Answer 13.

This thickening of the uterine wall in females is not permanent. If the egg, the female germ cell, gets fertilised, it develops into a single-celled zygote. However, if fertilisation does not occur, the released egg and the thickened lining are shed off, resulting in menstruation.

The single-celled zygote starts multiplying to become an embryo, which travels down the fallopian tube and gets embedded in the uterine wall, resulting in pregnancy. During pregnancy, no more eggs are released, the thickened lining is discharged only after 36 weeks, and the baby is expelled from the womb.

Question 14. A human gamete has ________ sex chromosome(s).

1. Four
2. Half
3. Two
4. One

Answer 14.

The correct option is A. one.

A human cell has a total of 46 chromosomes in total. Of these 46 chromosomes, 44, 22 pairs are autosomes, and 2 are sex chromosomes. Chromosomes occur in pairs, and hence, there are 23 pairs. A cell that has 23 pairs of chromosomes is called a diploid. Diploid cells go through division, and their number reduces to half,  i.e., producing haploid cells having only 23 chromosomes, without any pairs. These cells are also called gametes. Thus, gametes have only one sex chromosome.

Question 15. What is Adam’s apple?

Answer 15:

Adam’s apple: The protruding part of the boy in the throat is called Adam’s apple.

The enlarged voice box, or larynx, gets enlarged and visible from the outside in boys at puberty. This makes the voices of boys hoarse.

Question 16. Which among the following is a change seen in girls during Puberty?

1. Growth of facial hair
2. Cracking of voice
3. Breast development
4. Broad shoulders

Answer 16 : (C) Breast development

Breast development is one of the major and important changes in girls during Puberty. In girls, the region below the waist gets wider during Puberty, while in boys, the chest becomes wider, and the shoulders become broad.

Question 17. Salma had really soft and smooth skin during her childhood. As she entered adolescence, she started developing pimples on her face. A skin specialist advised her to wash her face at regular intervals during the day. Can you explain the reasons for the appearance of pimples on the face and suggest ways to prevent them?  

Answer 17: 

After the period of adolescence, the activity of sweat glands (which are also known as sudoriferous or the sudoriferous glands) and the sebaceous glands, which are small oil-producing glands increases their secretion. The increase in the secretion of these glands leads to the release of more and more oil and sweat, which get collected in the various pores present on the skin. Thus, these pores get blocked. Bacteria start growing there, leading to the development of various kinds of pimples on the face.

As Salma entered her adolescence, her sweat and sebaceous glands increased their secretion, resulting in the pimples on her face. If Salma had washed her face regularly and kept it clean and dry, she could have gotten rid of her pimples.

Question 18. Write a short note on Puberty.

Answer 18:

Puberty is a stage in a person’s life when their body and their reproductive systems undergo changes that lead to sexual maturity. The most significant change throughout Puberty is when boys and girls become reproductively competent.In some females, puberty can start one year or two earlier than in boys.During the commencement of the stage of Puberty, a person goes through various changes. It will vary between males and females, along with the magnitude of these alterations. Each person changes, such as height gain, bodily form change, voice change, sex organ growth, and mental, intellectual, and emotional maturation. Visible traits that are external in nature emerge in girls and boys during Puberty, aid in sex differentiation, and are very unrelated to reproduction. The following are some of the secondary sexual characteristics:

Boys

The development of facial, abdomen, underarm, chest, and pubic hair are examples of body hair growth in boys. The chest and shoulders are seen to expand, and the body develops muscle. The skin becomes rough and porous, and sweat and sebaceous gland secretions will rise. The larynx, also called Adam’s apple or voice box, protrudes, resulting in a deep, husky voice.

Girls

Some changes include breast enlargement, body hair development, particularly in the underarm and pubic regions, and hip enlargement. Fat distribution has shifted—more fat beneath the skin, particularly in the hips, buttocks, and thighs. Secondary reproductive organs are developing.

Question 19. The information below refers to which of the following hormones- (i) Glands secreting the hormone- are located on top of the kidneys. (ii) Converts glycogen into glucose. (iii) Increases blood pressure.

1. Testosterone
2. Insulin
3. Adrenaline
4. Progesterone

Answer 19: (C) Adrenaline

The adrenal glands of the body secrete adrenaline. These glands are located on top of the kidneys. The adrenaline hormone prepares the body to fight or run away during an emergency. Its effects involve increased heart rate, blood pressure, breathing rate, blood glucose level, etc.

Question 20. Write a note on the endocrine glands and the various organs involved in maturation during the date of adolescence.

Answer 20:

An endocrine system is a collection of various ductless glands that secrete chemical molecules called hormones. These hormones control physiological processes and function in different systems. They immediately inject their vivid secretions into the circulation of the body. Hormones frequently have long distances between their source and the location of the action.

Testosterone

Testosterone is the predominant male sex hormone. It is responsible for developing different secondary sexual traits, the development of the male reproductive system, and the generation of male gametes, like sperm. Only during the period of Puberty do the testes begin to secrete testosterone.

Estrogen/oestrogen is the predominant female sex hormone. It is in charge of developing the female reproductive system, the creation of the female gametes (ova), various secondary sexual traits, and the menstrual cycle in girls. After puberty, the ovaries start the release this hormone.

Thyroid Gland

The gland is shaped like a butterfly. It is located in the neck. The thyroid gland secretes the thyroxine hormone. This hormone is vital because it keeps various metabolic functions in check. A lack of this particular hormone can cause the thyroid gland to enlarge, resulting in goitre.

Pancreas

The pancreas is an abdominal organ surrounded by the spleen, liver, and small intestine and is placed behind the stomach. It is a crucial element of the digestive system that regulates blood sugar levels.

Pancreatic enzymes such as amylase, proteases, and lipases enter the duodenum during digestion. These different enzymes aid in the digestion of proteins, sugar, and lipids. The pancreas also contains islets of Langerhans, which produce hormones like insulin and glucagon in the bloodstream.

Benefits of Solving Important Questions Class 8 Science Chapter 10

Important Questions Class 8 Science Chapter 10 by Extramarks provides simplified and clear answers to every question. All questions asked are very likely to be asked in exams. Hence, students are advised to go through and revise them thoroughly. Step-by-step solutions, as well as MCQ or fill-in-the-blank explanations, assist students in understanding all concepts discussed in each chapter with clarity and resolve doubts about the particular concept being discussed. After revision of MCQs, short answers, medium answers, and long answer questions provided with simplified solutions, students can get well versed with the question pattern and understand the weightage of the chapter.

Furthermore, the different benefits of referring to Important Questions Class 8 Science Chapter 10 are as given below:

• The Extramarks team has provided stepwise solutions to every question, which helps students revise and understand all the important theoretical concepts mentioned in the chapter, which helps students score good marks in their exams.
• Students can entirely rely on the solutions given as they have been compiled carefully per the latest CBSE syllabus and NCERT guidelines.
• The questions provided by Extramarks are likely to be asked in the examinations. This helps students get a basic idea and understand the pattern of the questions that can be expected to be asked in the exams.
• The Science faculty at Extramarks are experts and have several years of teaching experience in Science and related subjects.
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