The following 20 Multiple Choice Questions (MCQ) are based on
Chapter 2: The Invisible Living World: Beyond Our Naked Eye from the NCERT Class 8
Science textbook Curiosity. Each question has four options - select the
best answer and click to check.
Instructions: Read each question carefully. Choose the most
appropriate option from (a), (b), (c), or (d). Click
Show Answer to reveal the correct answer with explanation.
Multiple Choice Questions
1Why are microscopes important in biology?
(a) They make distant stars visible
(b) They reveal objects too small for the naked eye
(c) They create microorganisms
(d) They eliminate the need for observation
(b) is correct
Microscopes magnify tiny structures and organisms that human eyes cannot resolve.
2What is the basic unit of a living organism?
(a) Cell
(b) Tissue
(c) Organ system
(d) Organ
(a) is correct
A cell is the smallest structural and functional unit of life.
3Who used a simple microscope to observe tiny living organisms in water?
(a) C. V. Raman
(b) Michael Faraday
(c) Antonie van Leeuwenhoek
(d) Isaac Newton
(c) is correct
Leeuwenhoek's improved lenses revealed microorganisms previously invisible to people.
4Which structure controls the activities of many cells?
(a) Vacuole only
(b) Cell membrane
(c) Nucleus
(d) Cell wall
(c) is correct
The nucleus contains genetic material and helps coordinate cell activities.
5The cell membrane mainly:
(a) Controls movement of substances into and out of the cell
(b) Produces all food
(c) Makes the cell visible without a microscope
(d) Occurs only in plants
(a) is correct
It forms the living boundary and regulates exchange with the surroundings.
6Which structure gives additional support to a plant cell?
(a) Nucleus
(b) Cytoplasm
(c) Cell membrane only
(d) Cell wall
(d) is correct
The rigid cell wall surrounds the cell membrane in plant cells.
7Why do cells have different shapes?
(a) All cells are actually spherical
(b) Only size matters
(c) Shape is unrelated to function
(d) Their shapes suit different functions
(d) is correct
A nerve cell, muscle cell and leaf cell differ because structure supports function.
8Which sequence shows levels of organisation correctly?
(a) Cell - organ - tissue - organism
(b) Cell - tissue - organ - organ system - organism
(c) Organism - cell - organ - tissue
(d) Tissue - cell - organ system - organ
(b) is correct
Cells cooperate in tissues, tissues build organs, and organs form systems within an organism.
9Microorganisms are organisms that:
(a) Can generally be observed only with magnification
(b) Are always harmful
(c) Live only in water
(d) Are all plants
(a) is correct
Most microbes are too small to see clearly with the naked eye.
10Which group includes yeast and bread mould?
(a) Fungi
(b) Protozoa
(c) Microalgae
(d) Bacteria
(a) is correct
Yeast and moulds are fungi.
11Amoeba is classified as a:
(a) Fungus
(b) Virus
(c) Bacterium
(d) Protozoan
(d) is correct
Amoeba is a unicellular protozoan.
12Which microorganism helps dough rise?
(a) Virus
(b) Yeast
(c) Amoeba
(d) Rhizobium
(b) is correct
Yeast ferments sugars and releases carbon dioxide that inflates the dough.
13The gas released when yeast ferments sugar is mainly:
(a) Oxygen
(b) Carbon dioxide
(c) Nitrogen
(d) Hydrogen
(b) is correct
Carbon dioxide bubbles make bread and cakes soft and fluffy.
14Which bacterium helps convert milk into curd?
(a) Rhizobium
(b) Plasmodium
(c) Amoeba
(d) Lactobacillus
(d) is correct
Lactobacillus converts milk sugar into lactic acid, giving curd its taste and texture.
15Microorganisms acting on dead matter are important because they:
(a) Remove all soil
(b) Produce only disease
(c) Stop nutrient cycling
(d) Decompose waste and return nutrients
(d) is correct
Decomposers recycle materials and help keep environments clean.
16Rhizobium benefits pulse crops by:
(a) Producing bread
(b) Causing leaf disease
(c) Helping supply usable nitrogen
(d) Removing all soil water
(c) is correct
Rhizobium in root nodules fixes atmospheric nitrogen into useful compounds.
17Why may bean farmers need less nitrogen fertiliser?
(a) Beans do not require nitrogen
(b) Nitrogen-fixing bacteria live in their root nodules
(c) Their roots make nitrogen gas
(d) Fungi remove every nutrient
(b) is correct
The symbiosis with Rhizobium helps legumes obtain nitrogen.
18Keeping bread in a refrigerator slows mould growth mainly because:
(a) Cold creates more fungi
(b) Bread becomes a cell
(c) Air disappears completely
(d) Lower temperature slows microbial activity
(d) is correct
Most spoilage microbes grow more slowly at low temperature.
19Microalgae are environmentally important because many of them:
(a) Live only in deserts
(b) Are visible as large trees
(c) Release oxygen and support aquatic food webs
(d) Destroy all dissolved oxygen
(c) is correct
Through photosynthesis, microalgae produce oxygen and form a base for aquatic ecosystems.
20Which statement about microbes is correct?
(a) All microbes are identical
(b) All microbes cause disease
(c) Microbes can be useful, harmful or harmless
(d) No microbe helps humans
(c) is correct
Their roles range from fermentation and decomposition to infection, while many have no harmful effect.
What is covered in CBSE Class 8 Science Chapter 2 The Invisible Living World: Beyond Our Naked Eye?
This chapter covers all key topics from The Invisible Living World: Beyond Our Naked Eye as per CBSE 2026-27 syllabus.
Is this MCQ Test useful for CBSE board exams?
Yes, designed for CBSE Class 8 board exam preparation covering the complete syllabus.
Are these CBSE Class 8 Science MCQ Test updated for 2026-27?
Yes, all content at eBookPublisher is updated as per the latest 2026-27 CBSE syllabus.
How many chapters are in CBSE Class 8 Science?
All chapters of CBSE Class 8 Science are covered at eBookPublisher with free MCQ Test for each chapter.
Can I study The Invisible Living World: Beyond Our Naked Eye online for free?
Yes, complete MCQ Test for The Invisible Living World: Beyond Our Naked Eye is available free at eBookPublisher. Study online directly — no download needed.
Where can I get a complete MCQ Test book for CBSE Class 8 Science?
You can purchase the complete expert-crafted MCQ Test book for CBSE Class 8 Science at eBookPublisher.in. Instant PDF download after payment.
