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

These Class 8 Science MCQ and Class 8 Science Chapter 2 The Invisible Living World: Beyond Our Naked Eye MCQ Questions Online Test with Answers focus on both theory and practical applications.

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

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

Class 8 Science Chapter 2 The Invisible Living World: Beyond Our Naked Eye MCQ Questions with Answers

Question 1.
What type of microorganism is yeast?
(a) Algae
(b) Protozoa
(c) Bacteria
(d) Fungi
Answer:
(d) Fungi

Question 2.
Which gas is released during yeast fermentation that makes the dough rise?
(a) Oxygen
(b) Nitrogen
(c) Carbon dioxide
(d) Hydrogen
Answer:
(c) Carbon dioxide

Question 3.
Which microorganism helps in curd formation?
(a) Lactobacillus
(b) Rhizobium
(c) Spirulina
(d) Mould
Answer:
(a) Lactobacillus

Question 4.
Rhizobium bacteria live in the root nodules of which plants?
(a) Wheat and rice
(b) Beans and peas
(c) Mango and banana
(d) Apple and orange
Answer:
(b) Beans and peas

Question 5.
What is the function of Rhizobium?
(a) Produces alcohol
(b) Kills viruses
(c) Traps nitrogen from the air
(d) Forms algae
Answer:
(c) Traps nitrogen from the air

Question 6.
Which of the following is unicellular?
(a) Human
(b) Yeast
(c) Mould
(d) Tree
Answer:
(b) Yeast

Question 7.
Spirulina is an example of
(a) Virus
(b) Protozoa
(c) Microalga
(d) Fungus
Answer:
(c) Microalga

Question 8.
What is used in bread-making to make it soft and fluffy?
(a) Sugar
(b) Salt
(c) Yeast
(d) Vinegar
Answer:
(c) Yeast

Question 9.
Which of the following lacks a well-defined nucleus?
(a) Algae
(b) Fungi
(c) Plant cell
(d) Bacterial cell
Answer:
(d) Bacterial cell

Question 10.
In the bread slice experiment, which condition supports more microbial growth?
(a) Dry and cold
(b) Dry and hot
(c) Moist and warm
(d) Moist and cold
Answer:
(c) Moist and warm

Question 11.
Which condition is most favourable for maximum microbial activity in the decomposition of fruit waste?
(a) Dry and cold
(b) Moist and warm
(c) Wet and cold
(d) Dry and hot
Answer:
(b) Moist and warm

Question 12.
Which of the following statements best explains why curd forms faster in summer than in winter?
(a) More milk is available in summer
(b) Lactobacillus dies in winter
(c) Warmth in summer speeds up bacterial growth
(d) Curd requires sunlight to form
Answer:
(c) Warmth in summer speeds up bacterial growth

Question 13.
In the bread mould experiment, what would happen if the bread were sealed in an airtight container without moisture?
(a) Mould will grow faster
(b) Mould will not grow
(c) Mould will turn green instantly
(d) Only bacteria will grow
Answer:
(b) Mould will not grow

Question 14.
Which component is not required for yeast fermentation to occur?
(a) Sugar
(b) Water
(c) Sunlight
(d) Warmth
Answer:
(c) Sunlight

Question 15.
What turns lime water milky in the yeast experiment?
(a) Oxygen
(b) Nitrogen
(c) Carbon dioxide
(d) Alcohol
Answer:
(c) Carbon dioxide

Question 16.
Why do legumes reduce the need for chemical fertilizers?
(a) They require very little water
(b) They have shallow roots
(c) They trap nitrogen from the air through bacteria
(d) They grow only in rainy seasons
Answer:
(c) They trap nitrogen from the air through bacteria

Question 17.
Which of these microorganisms is correctly matched with its product?
(a) Rhizobium – Alcohol
(b) Lactobacillus – Curd
(c) Yeast – Oxygen
(d) Spirulina – Vinegar
Answer:
(b) Lactobacillus – Curd

Question 18.
Which structural feature is absent in bacterial cells?
(a) Cell wall
(b) Cytoplasm
(c) Nucleus
(d) DNA
Answer:
(c) Nucleus

Question 19.
What is the function of the gas produced during yeast activity in dough?
(a) Prevents spoilage
(b) Makes it sour
(c) Makes it rise and fluffy
(d) Adds protein
Answer:
(c) Makes it rise and fluffy

Question 20.
Which of the following organisms is both useful as food and an oxygen producer?
(a) Mould
(b) Spirulina
(c) Yeast
(d) Rhizobium
Answer:
(b) Spirulina

Question 21.
Why is fermentation considered an anaerobic process?
(a) It occurs in sunlight
(b) It releases nitrogen
(c) It does not require oxygen
(c) It kills bacteria
Answer:
(c) It does not require oxygen

Question 22.
In which part of legume plants do nitrogen-fixing bacteria live?
(a) Leaves
(b) Stems
(c) Root nodules
(d) Flowers
Answer:
(c) Root nodules

Question 23.
Which experiment can prove that yeast is alive and actively growing?
(a) Keeping it in sunlight
(b) Mixing it with a cold sugar solution
(c) Mixing it with a warm sugar solution and observing gas formation
(d) Boiling it in water
Answer:
(c) Mixing it with a warm sugar solution and observing gas formation

Question 24.
How does Spirulina support environmental sustainability?
(a) Fixes nitrogen in roots
(b) Produces alcohol
(c) Produces oxygen and grows in less space
(d) Breaks down waste in landfills
Answer:
(c) Produces oxygen and grows in less space

Question 25.
What would happen if all decomposer microorganisms disappeared from Earth?
(a) Food production would increase
(b) No curd or bread could be made
(c) Waste and dead matter would accumulate
(d) Plants would grow faster
Answer:
(c) Waste and dead matter would accumulate

The Invisible Living World: Beyond Our Naked Eye Class 8 Fill in the blanks

Question 1.
Yeast converts sugar into alcohol and _______________ gas during the process of fermentation.
Answer:
Carbon Dioxide

Question 2.
_______________ is the part of the cell that controls all its activities.
Answer:
Nucleus

Question 3.
The _______________ in plant cells helps in the process of photosynthesis.
Answer:
Chloroplast

Question 4.
When carbon dioxide is passed through lime water, it turns _______________
Answer:
Milky

Question 5.
The process of converting sugar into alcohol using microorganisms is called _______________
Answer:
Fermentation

Question 6.
In bread making, yeast helps make the dough rise by producing _______________
Answer:
Carbon Dioxide

Question 7.
Microorganisms such as Rhizobium help in _______________ fixation in leguminous plants.
Answer:
Nitrogen

Question 8.
The _______________ provides structural support and shape to plant cells.
Answer:
Cell Wall

Question 9.
_______________ is a jelly-like substance found inside cells that contains all the cell organelles.
Answer:
Cytoplasm

Question 10.
In the balloon experiment, the balloon inflates due to the gas released by _______________
Answer:
Yeast

Question 11.
The _______________ is a selectively permeable membrane that surrounds all cells.
Answer:
Cell Membrane

Question 12.
Microorganisms grow best when there is enough warmth, moisture, air, and _______________
Answer:
Nutrients

Question 13.
The presence of _______________ in test tube B proves that gas was produced during the fermentation process.
Answer:
An Inflated Balloon

Question 14.
Dried leaves in compost pits provide _______________ to balance the nitrogen-rich food waste.
Answer:
Carbon

Question 15.
In an experiment with bread slices, the one near the sink is more likely to grow mould because of higher _______________ and temperature.
Answer:
Humidity

The Invisible Living World: Beyond Our Naked Eye Class 8 True or False

Question 1.
Yeast produces oxygen during fermentation, which causes balloons to inflate in test tube experiments.
Answer:
False

Question 2.
The lime water test is used to detect the presence of carbon dioxide gas.
Answer:
True

Question 3.
Only bacterial cells have chloroplasts to carry out photosynthesis.
Answer:
False

Question 4.
Rhizobium bacteria in root nodules of legumes can fix atmospheric nitrogen into a form usable by plants.
Answer:
True

Question 5.
Fungal growth is faster in cold, dry conditions.
Answer:
False

Question 6.
In an experiment, if lime water remains clear after gas is passed through it, the gas is definitely carbon dioxide.
Answer:
False

Question 7.
All microorganisms are harmful and cause diseases.
Answer:
False

Question 8.
Bread becomes softer and fluffier because yeast releases carbon dioxide gas during dough fermentation.
Answer:
True

Question 9.
The cytoplasm is only found in animal cells.
Answer:
False

Question 10.
When sugar is mixed with warm water and yeast, the process of fermentation begins.
Answer:
True

Question 11.
The nucleoid is a membrane-bound structure found only in plant cells.
Answer:
False

Question 12.
Dried leaves added to compost help balance the carbon and nitrogen ratio needed for effective decomposition.
Answer:
True

Question 13.
In the absence of air, microorganisms can still grow efficiently on bread.
Answer:
False

Question 14.
If yeast is not added to the sugar solution in an experiment, the lime water will still turn milky.
Answer:
False

Question 15.
Microorganisms can grow in extreme environments like hot springs, acidic lakes, and deep oceans.
Answer:
True

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