NCERT Solutions for Class 8 Science Chapter 2 - The Invisible Living World: Beyond Our Naked Eye

NCERT Solutions For Class 8 Science Chapter 2 - PDF Download

The PDF of the chapter, The Invisible Living World: Beyond Our Naked Eye, can be downloaded from the link given below. Students can use this anytime for doing revision and completing homework. The NCERT Solutions for Class 8 are prepared in simple language to help students understand all concepts clearly.

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Access to Class 8 Science Chapter 2 Solutions (Exercise Questions)

The detailed answers to all the textbook questions are given below. These solutions are based on the latest syllabus and are useful for quick revision before exams. Studying through The Invisible Living World: Beyond Our Naked Eye questions and answers helps students know about microorganisms.

Question 1: Various parts of a cell are given below. Write them in the appropriate places in the following diagram.

• Nucleus

• Cytoplasm

• Chloroplast

• Cell wall

• Cell membrane

• Nucleoid

Answer:

Question 2: Aanandi took two test tubes and marked them A and B. She put two spoonfuls of sugar solution in each of the test tubes. In test tube B, she added a spoonful of yeast. Then she attached two incompletely inflated balloons to the mouth of each test tube. She kept the setup in a warm place, away from sunlight.

(i) What do you predict will happen after 3–4 days? She observed that the balloon attached to test tube B was inflated. What can be a possible explanation for this?

(a) Water evaporated in test tube B and filled the balloon with the water vapour.

(b) The warm atmosphere expanded the air inside test tube B, which inflated the balloon.

(c) Yeast produced a gas inside test tube B, which inflated the balloon.

(d) Sugar reacted with warm air, which produced gas, eventually inflating the balloon.

Answer: The correct answer is option (c) Yeast produced a gas inside the test tube B, which inflated the balloon.

Explanation: Yeast is a type of microorganism, and it belongs to the group of fungi. Like other living organisms, yeast respires and breaks down food to release energy. During this process, it releases carbon dioxide gas, which gets trapped in the balloon and causes inflation.

(ii) She took another test tube, 1/4 filled with lime water. She removed the balloon from test tube B in such a manner that the gas inside the balloon did not escape. She attached the balloon to the test tube with lime water and shook it well. What do you think she wants to find out?

Answer: By doing this experiment, Anandi wants to find out which gas is released by the yeast. The gas, which is trapped in the balloon, when released in the lime water, makes the lime water milky. And if the lime water turns milky, it proves that the gas produced is carbon dioxide (CO₂).

Question 3: A farmer was planting wheat crops in his field. He added nitrogen-rich fertiliser to the soil to get a good yield of crops. In the neighbouring field, another farmer was growing bean crops, but she preferred not to add nitrogen fertiliser to get healthy crops. Can you think of the reasons?

Answer: Roots of certain plants, such as beans, have root nodules that contain Rhizobium bacteria. These bacteria trap the nitrogen from the air and convert it into a form that plants can use. This naturally increases the level of nitrogen in the soil, and that’s why these plants do not need nitrogen fertilisers.

Question 4: Snehal dug two pits, A and B, in her garden. In pit A, she put fruit and vegetable peels and mixed them with dried leaves. In pit B, she dumped the same kind of waste without mixing it with dried leaves. She covered both the pits with soil and observed after 3 weeks. What is she trying to test?

Answer: Snehal is trying to test how the presence of dried leaves affects the process of decomposition.

Dried leaves balance the content of dry and wet waste and make the decomposition process faster. On the other hand, in pit B, without dried leaves, the waste remains wet for a long time. This makes the process of decomposition slow.

Question 5: Identify the following microorganisms:

(i) I live in every kind of environment, and inside your gut.

(ii) I make bread and cakes soft and fluffy.

(iii) I live in the roots of pulse crops and provide nutrients for their growth.

Answer:

(i) I live in every kind of environment, and inside your gut - Bacteria

(ii) I make bread and cakes soft and fluffy - Yeast

(iii) I live in the roots of pulse crops and provide nutrients for their growth - Rhizobium

Question 6: Devise an experiment to test that microorganisms need optimal temperature, air, and moisture for their growth.

Answer: Given below is an experiment to test that microorganisms need an optimal temperature, air, and moisture for their growth.

Things Required

• 3 small glass jars

• Cooked rice

• Water spray bottle

Question 7: Take 2 slices of bread. Place one slice on a plate near the sink. Place the other slice in the refrigerator. Compare after three days. Note your observations. Give reasons for your observations.

Answer: After 3 days, the bread slice placed near the sink shows the growth of microbes such as fungus. While the bread, which is placed in the refrigerator, remains the same.

Reason: Microorganisms like fungi grow faster in warm and moist conditions, which are present near the sink. On the other hand, the temperature of the refrigerator is very low, which slows down the growth of microbes. That’s why the bread stays fresh in the refrigerator for a long time.

Question 8: A student observes that when curd is left out for a day, it becomes more sour. What are two possible explanations for this observation?

Answer: Two possible explanations for this observation are given below:

• The curd contains many types of bacteria. One of them is Lactobacillus. When the curd is left out for a day, these bacteria keep multiplying and produce lactic acid, which makes the curd sour.

• These Lactobacillus bacteria grow well in warm conditions, resulting in the production of more acid, which makes the curd sour.

Question 9: Observe the set-up given in the diagram and answer the following questions.

(i) What happens to the sugar solution in flask A?

(ii) What do you observe in test tube B after four hours? Why do you think this happened?

(iii) What would happen if yeast were not added to flask A?

Answer:

(i) Yeast, like other organisms, breaks down food to release energy. In flask A, the yeast undergoes the process of fermentation and breaks down the sugar molecules. During this process, it produces carbon dioxide and some alcohol.

(ii) The lime water present in the test tube B turns milky after four hours. It happens because the carbon dioxide produced in flask A passes into test tube B. This causes the lime water to be milky.

(iii) If yeast is not added to flask A, then no fermentation occurs, so carbon dioxide will not be produced. As a result, the lime water present in test tube B does not turn milky.

Also, check the NCERT Books and the NCERT Syllabus here

• NCERT Books Class 8 Science

• NCERT Syllabus Class 8 Science

• NCERT Books Class 8

• NCERT Syllabus Class 8

Approach to Solve Questions of Class 8 Science Chapter 2 Solutions

To answer the questions of this chapter, it is important for students to understand the topics. The Invisible Living World: Beyond Our Naked Eye questions and answers introduces tiny organisms and their roles in our lives. Provided below are a few steps that students can follow to answer the questions effectively.

1. Read the chapter carefully and understand how these microorganisms live around us in different places, like soil, water, and air.

2. Make a comparison table to know the differences between plant and animal cells. Students can refer to the NCERT Solutions for Class 8 Science Chapter 2, The Invisible Living World: Beyond Our Naked Eye.

3. Try to understand how cells are discovered and why they are known as the basic unit of life.

4. Practice remembering definitions and diagrams, such as the structure of cells. Understand the role of microbes in the environment provided in The Invisible Living World: Beyond Our Naked Eye, NCERT PDF.

5. Solve all the exercises given in the NCERT Solutions for Class 8 Science to check the knowledge and improve problem-solving skills.

NCERT Solutions For Class 8th: Subject-wise

• NCERT Solutions for Class 8 Maths

Important Topics of Chapter 2 NCERT Class 8 Science

Given below is the list of the important topics from this chapter that will help students revise. For gaining knowledge of these topics, students can refer to the NCERT Solutions for Class 8 Science Chapter 2 The Invisible Living World: Beyond Our Naked Eye.

• Cells: The basic unit of life

• Discovery of cells and cell structure

• Different types of cells

• Levels of organisation

• Microorganisms

• Role of microbes in the environment

• Microorganisms and Food

Important Question from Class 8 Science Chapter 2 Solutions

Provided below is an important question that increases the understanding of the concept. To score well in the exam, it is very important to practice questions of different types. For this purpose, students can depend on The Invisible Living World: Beyond Our Naked Eye Class 8 Solutions.

Question 1: The process by which yeast helps in making bread rise is called:

Options
(a) Fermentation
(b) Photosynthesis
(c) Respiration
(d) Decomposition

Answer: The correct answer is option (a), Fermentation

Explanation: Yeast breaks down sugar and produces a gas called carbon dioxide during fermentation. This gas makes the dough rise and become soft and fluffy.

NCERT Solutions for Class 8 Science: Chapter-wise

Given below are the solution links for all chapters. Students can refer to these to perform well in the exams.