NCERT Class 8 Science MCQ | Chapter 2: The Invisible Living World: Beyond Our Naked Eye
1. Why can many microorganisms not be seen with the naked eye?
(A) They have no structure
(B) They are very small in size
(C) They live only in darkness
(D) They are always transparent
Answer: (B) They are very small in size
2. What is the main purpose of a microscope?
(A) To measure temperature
(B) To make tiny objects appear larger
(C) To change the colour of objects
(D) To measure the mass of cells
Answer: (B) To make tiny objects appear larger
3. Who published the book Micrographia in 1665?
(A) Antonie van Leeuwenhoek
(B) Robert Hooke
(C) Ananda Mohan Chakrabarty
(D) Louis Pasteur
Answer: (B) Robert Hooke
4. What did Robert Hooke observe when he examined a thin slice of cork?
(A) Blood cells
(B) Bacteria
(C) Small compartments resembling a honeycomb
(D) Chloroplasts
Answer: (C) Small compartments resembling a honeycomb
5. Why did Robert Hooke call the small compartments in cork “cells”?
(A) They were filled with water
(B) They reminded him of small rooms or compartments
(C) They were shaped like circles
(D) They could move independently
Answer: (B) They reminded him of small rooms or compartments
6. Who is known as the Father of Microbiology?
(A) Robert Hooke
(B) Antonie van Leeuwenhoek
(C) Ananda Mohan Chakrabarty
(D) Charles Darwin
Answer: (B) Antonie van Leeuwenhoek
7. Which scientist was the first to clearly observe and describe tiny living organisms such as bacteria and blood cells?
(A) Robert Hooke
(B) Antonie van Leeuwenhoek
(C) Isaac Newton
(D) Ananda Mohan Chakrabarty
Answer: (B) Antonie van Leeuwenhoek
8. Which substance is used to stain onion peel cells in the activity described in the chapter?
(A) Methylene blue
(B) Safranin
(C) Iodine
(D) Green pigment
Answer: (B) Safranin
9. Why is glycerin added while preparing the onion peel slide?
(A) To kill the cells
(B) To make the cells grow
(C) To prevent drying and improve clarity
(D) To change the cells into blue colour
Answer: (C) To prevent drying and improve clarity
10. Which three structures are described as the basic parts of a typical cell?
(A) Cell wall, chloroplast and vacuole
(B) Cell membrane, cytoplasm and nucleus
(C) Nucleus, chloroplast and mitochondria
(D) Cytoplasm, cell wall and vacuole
Answer: (B) Cell membrane, cytoplasm and nucleus
11. What is one important function of the cell membrane?
(A) It produces sunlight
(B) It separates one cell from another and controls the entry and exit of materials
(C) It gives green colour to plants
(D) It produces manure
Answer: (B) It separates one cell from another and controls the entry and exit of materials
12. Which part of the cell regulates the activities occurring inside the cell?
(A) Cell wall
(B) Cytoplasm
(C) Nucleus
(D) Vacuole
Answer: (C) Nucleus
13. What is the main role of the cell wall in a plant cell?
(A) It provides rigidity and strength
(B) It produces digestive juices
(C) It controls all cell activities
(D) It makes the cell move
Answer: (A) It provides rigidity and strength
14. Which cell structure contains many components and is the site where most life processes take place?
(A) Cytoplasm
(B) Cell wall
(C) Cell membrane
(D) Nucleus
Answer: (A) Cytoplasm
15. Which structure in plant cells contains chlorophyll and helps in photosynthesis?
(A) Vacuole
(B) Chloroplast
(C) Nucleus
(D) Cell wall
Answer: (B) Chloroplast
16. Which statement correctly describes a plant cell vacuole?
(A) It controls all activities of the cell
(B) It stores substances, helps remove waste, and helps maintain cell shape
(C) It produces chlorophyll
(D) It forms the cell membrane
Answer: (B) It stores substances, helps remove waste, and helps maintain cell shape
17. Why do nerve cells have an elongated and branched structure?
(A) To store more water
(B) To reach different parts of the body and pass messages quickly
(C) To perform photosynthesis
(D) To produce food
Answer: (B) To reach different parts of the body and pass messages quickly
18. Which is the correct order of levels of organisation in a multicellular organism?
(A) Organ → Cell → Tissue → Organism → Organ system
(B) Cell → Tissue → Organ → Organ system → Organism
(C) Tissue → Cell → Organ → Organism → Organ system
(D) Cell → Organ → Tissue → Organ system → Organism
Answer: (B) Cell → Tissue → Organ → Organ system → Organism
19. Which of the following is a unicellular organism mentioned in the chapter?
(A) Human
(B) Amoeba
(C) Plant
(D) Mushroom
Answer: (B) Amoeba
20. Which of the following microorganisms is a fungus?
(A) Amoeba
(B) Paramecium
(C) Yeast
(D) Rhizobium
Answer: (C) Yeast
21. Which microorganisms help break down plant and animal waste into simpler substances?
(A) Fungi and bacteria
(B) Only algae
(C) Only protozoa
(D) Viruses and algae
Answer: (A) Fungi and bacteria
22. What is decomposition?
(A) The production of food by plants
(B) The breakdown of complex substances into simpler substances by microorganisms
(C) The movement of microorganisms
(D) The growth of cells into tissues
Answer: (B) The breakdown of complex substances into simpler substances by microorganisms
23. Which bacterium helps in the formation of curd?
(A) Rhizobium
(B) Lactobacillus
(C) Amoeba
(D) Spirulina
Answer: (B) Lactobacillus
24. Why does dough become soft and fluffy when yeast is added?
(A) Yeast releases oxygen during photosynthesis
(B) Yeast produces carbon dioxide during respiration, forming bubbles in the dough
(C) Yeast absorbs all the water from the dough
(D) Yeast produces chlorophyll
Answer: (B) Yeast produces carbon dioxide during respiration, forming bubbles in the dough
25. What is an important role of Rhizobium bacteria living in the root nodules of legumes?
(A) They produce chlorophyll for the roots
(B) They trap nitrogen from the air and make it useful for plants
(C) They prevent plants from absorbing water
(D) They produce carbon dioxide for photosynthesis
Answer: (B) They trap nitrogen from the air and make it useful for plants
NCERT Class 8 Science MCQ | Chapter 2: The Invisible Living World: Beyond Our Naked Eye
Assertion–Reason Questions
Directions: Choose the correct option:
(A) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
(B) Both Assertion and Reason are true, but Reason is not the correct explanation of Assertion.
(C) Assertion is true, but Reason is false.
(D) Assertion is false, but Reason is true.
1. Assertion: A microscope helps us observe microorganisms that cannot be seen with the naked eye.
Reason: A microscope magnifies the size of tiny objects, making them visible to us.
Answer: (A)
2. Assertion: The nucleus is an important part of a cell because it regulates the activities of the cell.
Reason: The nucleus also regulates the growth of the cell.
Answer: (B)
3. Assertion: Nerve cells have a long and branched structure.
Reason: Their elongated and branched structure helps them reach different parts of the body and pass messages quickly.
Answer: (A)
4. Assertion: Yeast helps make dough soft and fluffy.
Reason: During respiration, yeast releases carbon dioxide, which forms bubbles in the dough.
Answer: (A)
5. Assertion: Growing legumes can help maintain the fertility of soil.
Reason: Rhizobium bacteria living in the root nodules of legumes trap nitrogen from the air and make it useful for plants.
Answer: (A)
