The Invisible Living World: Beyond Our Naked Eye Class 8 MCQs Science Chapter 2

The world around us is full of tiny living organisms that cannot be seen with our naked eyes. These microorganisms play an important role in nature, human health, food production, and the environment. In Class 8 Science, students learn about this fascinating invisible world through concepts related to microbes, diseases, food preservation, and useful microorganisms.

This article provides detailed explanations along with MCQ Questions for Class 8 Science with Answers to help students prepare effectively for school exams, Olympiads, and competitive tests. Students searching for CBSE class 8 science mcq chapter 2 with answers or Class 8 Science Chapter 2 MCQ with answers PDF can use this guide for quick revision and practice.

What is the Invisible Living World?

The invisible living world includes microorganisms such as bacteria, fungi, algae, protozoa, and viruses. These organisms are so tiny that they can only be seen using a microscope.

Microorganisms are found everywhere:

• In air
• In water
• In soil
• Inside plants and animals
• Even inside the human body

Download Class 8 Science MCQ with Answers Chapter 2 PDF

Students can download the Class 8 science chapter 2 PDF worksheet containing important MCQ questions based on the latest NCERT syllabus. The PDF is designed in a student-friendly format to make learning simple and effective.

The Invisible Living World: Beyond Our Naked Eye Class 8 MCQ with Answers

1. Which instrument is used to see microorganisms?

a) Telescope

b) Microscope

c) Periscope

d) Binocular

Answer: b) Microscope

2. Microorganisms are also called:

a) Insects

b) Animals

c) Microbes

d) Plants

Answer: c) Microbes

3. Which of the following is a bacterium?

a) Amoeba

b) Lactobacillus

c) Mushroom

d) Virus

Answer: b) Lactobacillus

4. Which microorganism is used in curd formation?

a) Virus

b) Bacteria

c) Algae

d) Protozoa

Answer: b) Bacteria

5. Which microorganism is used in bread making?

a) Yeast

b) Virus

c) Algae

d) Bacteria

Answer: a) Yeast

6. Yeast belongs to which group?

a) Bacteria

b) Protozoa

c) Fungi

d) Virus

Answer: c) Fungi

7. Which disease is caused by bacteria?

a) Cholera

b) Malaria

c) Dengue

d) Common cold

Answer: a) Cholera

8. Malaria is caused by:

a) Virus

b) Fungus

c) Protozoa

d) Bacteria

Answer: c) Protozoa

9. Dengue is caused by:

a) Fungus

b) Virus

c) Protozoa

d) Algae

Answer: b) Virus

10. Which of the following is NOT a microorganism?

a) Amoeba

b) Bacteria

c) Dog

d) Virus

Answer: c) Dog

11. The study of microorganisms is called:

a) Biology

b) Zoology

c) Microbiology

d) Botany

Answer: c) Microbiology

12. Which microorganism fixes nitrogen in soil?

a) Rhizobium

b) Amoeba

c) Virus

d) Yeast

Answer: a) Rhizobium

13. Which gas is fixed by bacteria in the nitrogen cycle?

a) Oxygen

b) Nitrogen

c) Carbon dioxide

d) Hydrogen

Answer: b) Nitrogen

14. Which microorganism causes the common cold?

a) Virus

b) Bacteria

c) Algae

d) Fungus

Answer: a) Virus

15. Pasteurization is mainly used for:

a) Preserving milk

b) Cleaning water

c) Cooking rice

d) Growing plants

Answer: a) Preserving milk

16. Who discovered pasteurization?

a) Newton

b) Einstein

c) Louis Pasteur

d) Galileo

Answer: c) Louis Pasteur

17. Which of the following helps in food preservation?

a) Moisture

b) Warm temperature

c) Refrigeration

d) Dust

Answer: c) Refrigeration

18. Vaccines help in:

a) Increasing height

b) Preventing diseases

c) Growing plants

d) Digestion

Answer: b) Preventing diseases

19. Tuberculosis mainly affects:

a) Eyes

b) Skin

c) Lungs

d) Bones

Answer: c) Lungs

20. Which disease spreads through contaminated water?

a) Cholera

b) Asthma

c) Diabetes

d) Cancer

Answer: a) Cholera

21. Amoeba belongs to:

a) Fungi

b) Protozoa

c) Virus

d) Algae

Answer: b) Protozoa

22. Which microorganism produces antibiotics?

a) Bacteria and fungi

b) Birds

c) Reptiles

d) Fish

Answer: a) Bacteria and fungi

23. Penicillin is obtained from:

a) Virus

b) Algae

c) Fungus

d) Protozoa

Answer: c) Fungus

24. Which of the following is an air-borne disease?

a) Cholera

b) Common cold

c) Malaria

d) Typhoid

Answer: b) Common cold

25. Which disease spreads through mosquito bites?

a) Malaria

b) Polio

c) Tuberculosis

d) Measles

Answer: a) Malaria

26. Which microorganism causes food spoilage?

a) Fungi

b) Bacteria

c) Both a and b

d) None of these

Answer: c) Both a and b

27. Blue-green algae can:

a) Fly

b) Fix nitrogen

c) Produce milk

d) Cause earthquakes

Answer: b) Fix nitrogen

28. Which microorganism is commonly found in ponds?

a) Amoeba

b) Tiger

c) Dog

d) Sparrow

Answer: a) Amoeba

29. The process of converting milk into curd is called:

a) Fermentation

b) Digestion

c) Respiration

d) Germination

Answer: a) Fermentation

30. Which vitamin is produced using bacteria?

a) Vitamin C

b) Vitamin D

c) Vitamin B12

d) Vitamin A

Answer: c) Vitamin B12

31. Which of the following is a fungal disease?

a) Ringworm

b) Dengue

c) Typhoid

d) Polio

Answer: a) Ringworm

32. Which microorganism is smallest in size?

a) Algae

b) Virus

c) Fungi

d) Protozoa

Answer: b) Virus

33. Which method removes moisture from food?

a) Drying

b) Boiling

c) Frying

d) Cooling

Answer: a) Drying

34. Salt is used in food preservation because it:

a) Adds color

b) Prevents microbial growth

c) Increases sweetness

d) Produces vitamins

Answer: b) Prevents microbial growth

35. Sugaring is commonly used to preserve:

a) Milk

b) Fruits

c) Rice

d) Wheat

Answer: b) Fruits

36. Which of these is useful algae?

a) Spirogyra

b) Chlamydomonas

c) Seaweed

d) All of these

Answer: d) All of these

37. Which microorganism causes typhoid?

a) Virus

b) Bacteria

c) Fungi

d) Protozoa

Answer: b) Bacteria

38. Vaccination provides:

a) Immunity

b) Hunger

c) Sleep

d) Weakness

Answer: a) Immunity

39. Which of these diseases is viral?

a) Chickenpox

b) Cholera

c) Ringworm

d) Malaria

Answer: a) Chickenpox

40. Which microorganism decomposes dead plants and animals?

a) Fungi and bacteria

b) Birds

c) Reptiles

d) Mammals

Answer: a) Fungi and bacteria

41. Which disease is prevented by the polio vaccine?

a) Malaria

b) Polio

c) Cholera

d) Dengue

Answer: b) Polio

42. The microorganism used in alcohol production is:

a) Yeast

b) Amoeba

c) Virus

d) Algae

Answer: a) Yeast

43. Which of the following is NOT useful?

a) Nitrogen fixation

b) Food spoilage

c) Medicine production

d) Curd formation

Answer: b) Food spoilage

44. Which microorganism causes plant diseases?

a) Bacteria

b) Fungi

c) Virus

d) All of these

Answer: d) All of these

45. The branch of science dealing with microorganisms is:

a) Astronomy

b) Chemistry

c) Microbiology

d) Ecology

Answer: c) Microbiology

46. Which microorganism is responsible for fermentation?

a) Yeast

b) Virus

c) Amoeba

d) Algae

Answer: a) Yeast

47. Which disease affects the respiratory system?

a) Tuberculosis

b) Malaria

c) Cholera

d) Ringworm

Answer: a) Tuberculosis

48. Which food item is prepared using bacteria?

a) Bread

b) Curd

c) Cake

d) Rice

Answer: b) Curd

49. Which of the following is a protozoan disease?

a) Dengue

b) Typhoid

c) Malaria

d) Chickenpox

Answer: c) Malaria

50. Microorganisms can be useful in:

a) Agriculture

b) Medicine

c) Food preparation

d) All of these

Answer: d) All of these

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• Helps in quick revision before exams
• Useful for school exams, quizzes, and Olympiad preparation
• Includes concept-based and exam-oriented questions
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Tips to Prepare The Invisible Living World: Beyond Our Naked Eye MCQs Effectively

Preparing MCQs for The Invisible Living World: Beyond Our Naked Eye requires a clear understanding of microorganisms, their uses, harmful effects, and their role in daily life. This chapter is important for building a strong Science foundation in Class 8 and often includes concept-based objective questions in school exams and Olympiads. With the right preparation strategy, students can improve accuracy, confidence, and overall performance in Science.

Below are some expert tips to help students prepare effectively for MCQs from this chapter:

• Read the NCERT chapter thoroughly before solving MCQs.
• Understand the basic concepts of microorganisms and their types.
• Learn the differences between bacteria, fungi, viruses, algae, and protozoa.
• Focus on important topics like diseases, vaccination, and food preservation.
• Make short notes for quick revision.
• Memorize important scientific terms and definitions.
• Practice chapter-wise MCQs regularly.
• Solve class 8 previous year and sample paper questions.
• Attempt online MCQ tests to improve speed and accuracy.
• Revise diagrams and flowcharts related to microorganisms.
• Learn examples of useful and harmful microorganisms.
• Pay special attention to nitrogen fixation and the nitrogen cycle.
• Read all options carefully before choosing the correct answer.
• Avoid guesswork and use elimination methods for confusing questions.
• Revise mistakes from previous practice tests.
• Practice daily to improve confidence and exam performance.
• Use PDF notes and MCQ worksheets for offline revision.
• Stay consistent with revision before exams.
• Focus on concept clarity instead of rote learning.
• Take mock tests regularly to track improvement.