CBSE Class 8 Science Chapter 2: The Invisible Living World: Beyond Our Naked Eye — Assertion & Reason
CBSE Class 8 Science Assertion & Reason
Expert crafted · Instant PDF download · 2026-27
The following Assertion and Reason questions 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 — read both the Assertion (A) and Reason (R) carefully before selecting your answer.
How to attempt Assertion & Reason questions:
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is NOT the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is NOT the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.
Assertion & Reason Questions
1
Assertion (A): Robert Hooke was the first person to use the word 'cell' to describe the basic unit of life.
Reason (R): He observed small, empty spaces in a thin slice of cork under a microscope that reminded him of a honeycomb.
Reason (R): He observed small, empty spaces in a thin slice of cork under a microscope that reminded him of a honeycomb.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. In 1665, Robert Hooke observed cork cells using a self-designed microscope and coined the term 'cell' because the structures looked like small compartments or honeycombs.
2
Assertion (A): Antonie van Leeuwenhoek is known as the Father of Microbiology.
Reason (R): He wrote the famous book Micrographia showing detailed drawings of tiny things.
Reason (R): He wrote the famous book Micrographia showing detailed drawings of tiny things.
Answer: (c)
A is true, but R is false. While Leeuwenhoek is the Father of Microbiology for first observing living bacteria and blood cells, the book Micrographia was written and published by Robert Hooke.
3
Assertion (A): Plant cells are generally arranged compactly and look very firm in structure.
Reason (R): Plant cells have an extra outer layer called the cell wall that provides rigidity and strength.
Reason (R): Plant cells have an extra outer layer called the cell wall that provides rigidity and strength.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. The presence of a rigid cell wall outside the cell membrane gives plant cells structural support and a firm shape.
4
Assertion (A): Animal cells have large, empty-looking spaces called vacuoles to maintain the shape of the cell.
Reason (R): Vacuoles help plant cells store important substances and get rid of waste.
Reason (R): Vacuoles help plant cells store important substances and get rid of waste.
Answer: (d)
A is false, but R is true. Plant cells have large vacuoles that provide strength and support. Animal cells usually do not have vacuoles, and if they do, they are very small.
5
Assertion (A): Chloroplasts are plastids that make the plant appear green and help in photosynthesis.
Reason (R): Chloroplasts contain the green pigment called chlorophyll.
Reason (R): Chloroplasts contain the green pigment called chlorophyll.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Chlorophyll is the specific pigment stored inside chloroplasts that traps sunlight and facilitates photosynthesis in plants.
6
Assertion (A): Nerve cells (neurons) are elongated and possess branches.
Reason (R): The elongated and branched structure helps them reach different parts of the body and pass on messages quickly.
Reason (R): The elongated and branched structure helps them reach different parts of the body and pass on messages quickly.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. The shape of a cell is closely related to its function; the long, branched structure of neurons is perfectly suited for fast communication across the body.
7
Assertion (A): Microorganisms are small living beings that can be easily observed with the naked eye.
Reason (R): Amoeba and bacteria are examples of unicellular microorganisms.
Reason (R): Amoeba and bacteria are examples of unicellular microorganisms.
Answer: (d)
A is false, but R is true. Microorganisms (or microbes) are so small that they cannot be seen with the naked eye and require a microscope or foldscope to be observed.
8
Assertion (A): Viruses are considered different from other microorganisms like bacteria and fungi.
Reason (R): Viruses are acellular and can multiply only when they enter a living host cell.
Reason (R): Viruses are acellular and can multiply only when they enter a living host cell.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Unlike bacteria or fungi which have cellular structures and can multiply independently, viruses lack cellular structure (acellular) and require a living host to reproduce.
9
Assertion (A): Pickles and murabbas easily get infected by microorganisms if left outside.
Reason (R): Spices, salt, and sugar added to pickles act as preservatives that do not allow microorganisms to grow.
Reason (R): Spices, salt, and sugar added to pickles act as preservatives that do not allow microorganisms to grow.
Answer: (d)
A is false, but R is true. Pickles and murabbas generally do NOT get easily infected by microbes because the high concentration of salt or sugar acts as a preservative, preventing microbial growth.
10
Assertion (A): Microorganisms like fungi and bacteria are key players in cleaning the environment.
Reason (R): They break down dead plants, leaves, and animal waste into simpler, nutrient-rich manure.
Reason (R): They break down dead plants, leaves, and animal waste into simpler, nutrient-rich manure.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Decomposers break down organic waste, recycling nutrients back into the soil and keeping the environment clean.
11
Assertion (A): Yeast makes the dough for bread and cakes soft and fluffy.
Reason (R): Yeast produces lactic acid during respiration, which raises the dough.
Reason (R): Yeast produces lactic acid during respiration, which raises the dough.
Answer: (c)
A is true, but R is false. Yeast does make the dough fluffy, but it does so by releasing carbon dioxide (CO2) gas during respiration, not lactic acid. The trapped CO2 bubbles cause the dough to rise.
12
Assertion (A): Curd is formed when lukewarm milk is mixed with a little starter curd and kept in a warm place.
Reason (R): Lactobacillus bacteria present in the curd feed on milk sugar and ferment it to produce lactic acid.
Reason (R): Lactobacillus bacteria present in the curd feed on milk sugar and ferment it to produce lactic acid.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. The warm temperature is optimal for Lactobacillus bacteria to multiply rapidly, converting lactose sugar into lactic acid, which curdles the milk.
13
Assertion (A): Farmers grow leguminous plants like peas and beans in rotation with other crops to increase soil fertility naturally.
Reason (R): Rhizobium bacteria present in the root nodules of legumes trap atmospheric nitrogen and make it available to the plants.
Reason (R): Rhizobium bacteria present in the root nodules of legumes trap atmospheric nitrogen and make it available to the plants.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. This symbiotic relationship enriches the soil with nitrogen without the need for chemical fertilizers.
14
Assertion (A): Microalgae produce more than half of the Earth's oxygen supply.
Reason (R): Microalgae do not contain chlorophyll and cannot make their own food.
Reason (R): Microalgae do not contain chlorophyll and cannot make their own food.
Answer: (c)
A is true, but R is false. Microalgae are plant-like organisms that DO contain chlorophyll and make their own food using sunlight (photosynthesis), releasing large amounts of oxygen in the process.
15
Assertion (A): Bacterial cells have a well-defined nucleus covered by a nuclear membrane.
Reason (R): Instead of a true nucleus, bacterial cells contain a region called a nucleoid.
Reason (R): Instead of a true nucleus, bacterial cells contain a region called a nucleoid.
Answer: (d)
A is false, but R is true. Bacteria lack a well-defined nucleus and a nuclear membrane. Their genetic material is simply localized in a region known as the nucleoid.
❓ Frequently Asked Questions
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 Assertion & Reason useful for CBSE board exams?
Yes, designed for CBSE Class 8 board exam preparation covering the complete syllabus.
Are these CBSE Class 8 Science Assertion & Reason 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 Assertion & Reason for each chapter.
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