CBSE Class 9 Science Chapter 02 Cell The Building Block Of Life MCQs Set 01

Science Objective Questions and Answers: Chapter 02 Cell The Building Block Of Life

Explore reliable objective questions for Chapter 02 Cell The Building Block Of Life tailored for Class 9 learners. Utilizing these Science multiple-choice formats ensures thorough preparation and strengthens problem-solving speed for upcoming school assessments.

Download Chapter 02 Cell The Building Block Of Life MCQs with Answers

Navigate directly to the 50 objective questions for Chapter 02 Cell The Building Block Of Life using the digital viewer below. Each practice set includes verified answer keys, allowing students to instantly cross-check their work and identify areas requiring further revision.

Question: In science, what is the main purpose of building a simplified model of a real system, such as treating a moving car as a single point?
A. To make the study focus only on the details that matter for the question being asked
B. To make the object look more scientific and complex in diagrams
C. To completely replace the need for experiments and observations
D. To ensure every possible detail about the system is accounted for
Show Answer & Explanation

Answer: (A) To make the study focus only on the details that matter for the question being asked

Explanation:
Models deliberately leave out unimportant details so that attention stays on what actually matters for the question at hand, like ignoring air resistance while studying gravity's effect on a falling object.

Question: Why did Meghnad Saha treat the matter inside a star as a simple hot gas instead of tracking every atom and reaction?
A. He wanted to avoid mathematics entirely while studying stars
B. He believed atoms did not exist inside stars
C. He needed a simplification that still let him connect temperature to the colour of stars
D. He was only interested in describing the shape of stars
Show Answer & Explanation

Answer: (C) He needed a simplification that still let him connect temperature to the colour of stars

Explanation:
By ignoring many complicated processes and focusing on temperature, pressure, and ionisation, Saha created a workable model that successfully linked a star's colour to its temperature.

Question: According to the chapter, why does science assign precise, specific meanings to everyday words like force or reaction?
A. So that only trained scientists can ever understand these words
B. So that scientists worldwide can share observations and results without confusion
C. So that mathematics can be avoided in scientific writing
D. So that these words sound more impressive in textbooks
Show Answer & Explanation

Answer: (B) So that scientists worldwide can share observations and results without confusion

Explanation:
Everyday words carry loose meanings, but science needs unambiguous communication so results can be compared and built upon across the world; that is why terms are given fixed, agreed meanings.

Question: The chapter describes an equation as being more than just a calculation tool. What does this mean?
A. Equations are only useful for exams and have no real-world purpose
B. An equation is a compact way of stating how different quantities are related to one another
C. Equations replace the need to understand the situation being studied
D. Equations are simply lists of symbols scientists use to look advanced
Show Answer & Explanation

Answer: (B) An equation is a compact way of stating how different quantities are related to one another

Explanation:
The text explains that an equation compactly expresses relationships between quantities, helping us reason about a situation rather than just crunch numbers.

Question: Why is the symbol 'c' used for the speed of light rather than some other letter?
A. It stands for 'constant' in English
B. It was chosen randomly by early physicists
C. It comes from the Latin word celeritas, meaning speed
D. It is the first letter of the scientist who discovered light
Show Answer & Explanation

Answer: (C) It comes from the Latin word celeritas, meaning speed

Explanation:
Scientific symbols often trace back to historical and linguistic roots rather than convenient abbreviations; 'c' comes from the Latin term for speed, celeritas.

Question: A passenger aircraft once nearly ran out of fuel mid-flight. What was the real cause of this dangerous miscalculation?
A. The pilots ignored the fuel gauge warning lights
B. The ground crew calculated fuel using pounds per litre instead of the required kilograms per litre
C. The aircraft had a mechanical fault in its fuel tank
D. The airline underestimated the distance of the flight
Show Answer & Explanation

Answer: (B) The ground crew calculated fuel using pounds per litre instead of the required kilograms per litre

Explanation:
Confusing pounds with kilograms while computing fuel density led to a shortfall of about 15,000 litres of fuel, showing why sticking to standard SI units everywhere matters.

Question: What is the underlying reason kilograms and other standard units are used consistently across the world?
A. Local traditions decide how much a kilogram should weigh
B. International agreement on units prevents confusion and unfair trade
C. Every country invented the kilogram independently with the same value
D. Standard units make scientific writing look more formal
Show Answer & Explanation

Answer: (B) International agreement on units prevents confusion and unfair trade

Explanation:
• Units based on personal or local objects would vary from place to place
• This would create confusion in trade and unreliable scientific comparisons
• Agreed international standards fix this by making a kilogram mean the same thing everywhere

Question: How does a scientific law differ from a scientific theory, based on the distinction drawn in the chapter?
A. A law is untested while a theory is proven beyond doubt
B. A law only applies to living things while a theory applies to non-living things
C. A law describes a regular observed pattern, while a theory explains why that pattern happens
D. There is no real difference; the terms are used interchangeably in science
Show Answer & Explanation

Answer: (C) A law describes a regular observed pattern, while a theory explains why that pattern happens

Explanation:
The text gives Newton's laws of motion as describing an observed pattern (the jerk felt when a bus stops), while atomic theory goes further by explaining why molecules form the way they do.

Question: The chapter states that a theory in science is never just a guess. What does this imply about theories?
A. Theories are permanent truths that can never be revised
B. Theories are built on careful testing but remain open to change with new evidence
C. Theories are personal opinions of famous scientists
D. Theories only apply to biology and not to physics or chemistry
Show Answer & Explanation

Answer: (B) Theories are built on careful testing but remain open to change with new evidence

Explanation:
Unlike a casual guess, a theory rests on evidence and rigorous examination, yet it stays open to revision as fresh evidence emerges, which is part of why science stays reliable.

Question: In Varsha and Meghna's conversation about rain, why are questions with simple yes/no answers considered less useful for scientific testing?
A. Because yes/no questions cannot generate measurable evidence or reveal patterns
B. Because Varsha refuses to answer yes/no questions
C. Because scientific predictions never involve weather
D. Because yes/no answers are always factually incorrect
Show Answer & Explanation

Answer: (A) Because yes/no questions cannot generate measurable evidence or reveal patterns

Explanation:
Good scientific questioning digs for measurable data, like humidity percentages or wind speed, rather than settling for a vague yes or no that reveals little about actual evidence.

Question: What ultimately happens in science when a well-established theory's predictions repeatedly fail to match real observations?
A. The theory is immediately declared false and banned from textbooks
B. Scientists ignore the mismatch to protect the theory's reputation
C. Scientists review their assumptions, models, or measurements rather than relying on opinion
D. The observations are dismissed since theories are always correct
Show Answer & Explanation

Answer: (C) Scientists review their assumptions, models, or measurements rather than relying on opinion

Explanation:
Mismatches between prediction and evidence push scientists to re-examine what went wrong in their models or measurements, an openness to correction that the chapter calls science's greatest strength.

Question: The claim that eating food during an eclipse is harmful is used in the chapter to illustrate what scientific habit?
A. Accepting widely shared social media claims without question
B. Testing a claim by asking whether any real physical, chemical, or biological change actually occurs
C. Avoiding all discussion of astronomical events in science class
D. Relying on tradition rather than evidence to judge a claim
Show Answer & Explanation

Answer: (B) Testing a claim by asking whether any real physical, chemical, or biological change actually occurs

Explanation:
By asking whether temperature changes or food actually spoils in a shadow during an eclipse, one can show there's no real mechanism behind the myth, demonstrating how scientific questioning debunks unfounded claims.

Question: When estimating the litres of air breathed in a day, why did the chapter use two different methods (breath counting and balloon-filling rate) to arrive at similar answers?
A. To prove that breathing is exactly the same as blowing balloons
B. To show that cross-checking an estimate with a different approach helps confirm whether it is reasonable
C. To calculate the exact volume of a human lung
D. To demonstrate that estimation is unnecessary once one method is used
Show Answer & Explanation

Answer: (B) To show that cross-checking an estimate with a different approach helps confirm whether it is reasonable

Explanation:
Getting close results (around 8,640 and 10,000 litres) from two separate estimation approaches builds confidence that the rough figure is sensible, which is the whole point of estimation in science.

Question: Why does the chapter emphasise that real-world problems like climate change or disease usually cannot be solved using just one branch of science?
A. Because physics, chemistry, biology, and earth science exist as fully separate, unrelated fields in nature
B. Because such problems are too difficult for any scientific approach to solve
C. Because complex issues typically require combining ideas across multiple scientific disciplines together
D. Because mathematics has no role in solving practical problems
Show Answer & Explanation

Answer: (C) Because complex issues typically require combining ideas across multiple scientific disciplines together

Explanation:
Boundaries between physics, chemistry, biology and earth science are human ways of organising knowledge; nature itself doesn't respect these divisions, so tackling big issues needs ideas drawn from several fields at once, as with understanding how a mask filters viruses using physics, chemistry, and biology together.

Question: What is the broader message conveyed by describing science as guided by 'a magnifying glass and a compass' at the start of the chapter?
A. Science is purely about collecting random facts without any structure
B. Science requires both close observation and a sense of direction or purpose in inquiry
C. Only tools like magnifying glasses are useful in scientific study
D. Compasses are needed only for earth science topics like geography
Show Answer & Explanation

Answer: (B) Science requires both close observation and a sense of direction or purpose in inquiry

Explanation:
The magnifying glass stands for careful observation of patterns, while the compass represents choosing the right questions and models — together they capture that exploring science means observing carefully while staying purposeful, not wandering aimlessly.

Question: In the cricket shot example used to explain modelling, which of these would actually matter when predicting whether the ball clears the boundary?
A. The colour of the ball and the brand of the bat
B. The speed and direction with which the ball was hit
C. The amount of grass on the outfield
D. The stitching pattern at the seam of the ball
Show Answer & Explanation

Answer: (B) The speed and direction with which the ball was hit

Explanation:
The example makes clear that only quantities affecting the ball's flight path count, mainly its mass, speed and direction. Details like bat brand, ball colour or grass length make no real difference to whether it crosses the boundary, so they are safely ignored in a simple model.

Question: The chapter gives climbing a staircase as an example of applying a scientific principle. What does this reveal about the term 'principle' as used in the text?
A. A principle is a fixed numerical value that never changes
B. A principle is a broad idea that can be applied to make sense of a particular situation
C. A principle is the same as a mathematical equation
D. A principle is a claim that has not yet been tested
Show Answer & Explanation

Answer: (B) A principle is a broad idea that can be applied to make sense of a particular situation

Explanation:
Conservation of energy is described as a principle because it is a general idea that helps explain what happens in a specific case, here, the effort involved in climbing stairs. This is different from a law, which describes a pattern, or a theory, which explains why the pattern occurs.

Question: According to the chapter, why do weather forecasts tend to become less trustworthy the further ahead in time they try to predict?
A. Weather instruments stop working after a few hours
B. Small differences in starting conditions can grow larger over time and change the outcome
C. Forecasters deliberately avoid long-term predictions
D. Temperature and humidity are not measurable quantities
Show Answer & Explanation

Answer: (B) Small differences in starting conditions can grow larger over time and change the outcome

Explanation:
Weather depends on many interacting factors, and the text explains that tiny variations in these conditions can amplify as time passes, making the models less reliable further into the future even though they work well for the near term.

Question: Based on the chapter's description of good scientific habits, what is the correct order of steps when tackling a new problem in science?
A. Memorise a formula, apply it, then check the units
B. Make a rough guess, perform the experiment, then understand the situation
C. Understand the situation, identify the relevant quantities, then estimate to check if the answer is sensible
D. Calculate an exact answer first, then think about what the question was asking
Show Answer & Explanation

Answer: (C) Understand the situation, identify the relevant quantities, then estimate to check if the answer is sensible

Explanation:
The chapter recommends first grasping what is actually being studied, then picking out which quantities matter, and only afterwards making an approximate estimate to see whether the result feels reasonable. This habit builds intuition rather than relying purely on precise calculation.

Question: The example of how a surgical mask works is used in the chapter mainly to show what?
A. That physics alone can explain every technology we use
B. That real-world problems often need ideas from several branches of science combined together
C. That masks only became useful after the COVID-19 pandemic
D. That chemistry is more important than biology in everyday life
Show Answer & Explanation

Answer: (B) That real-world problems often need ideas from several branches of science combined together

Explanation:
Explaining how a mask filters particles draws on physics for particle motion, chemistry for the fibre material, biology for virus size, and mathematics for airflow modelling. The chapter uses this to show that the branches of science are not separate boxes but work together to solve practical problems.

Question: Why does the chapter specifically mention physicist Meghnad Saha and his image on an Indian postage stamp?
A. To show that stamps are a reliable source of scientific data
B. To give an example of an Indian scientist who used simplification to explain a real phenomenon
C. To prove that all stars are made of pure hydrogen gas
D. To argue that models should always include every possible detail
Show Answer & Explanation

Answer: (B) To give an example of an Indian scientist who used simplification to explain a real phenomenon

Explanation:
Saha's work on starlight is used as a real-life illustration of building a model: he ignored countless complex internal processes and focused only on temperature, pressure and ionisation, showing how deliberate simplification can still lead to powerful scientific explanations, including from an Indian scientist honoured on a stamp.

Question: Quantities such as mass, velocity, force and electric current are given short symbols like m, v, F and I. What is the main reason science does this?
A. To make textbooks shorter and cheaper to print
B. To create a precise, shared language that lets scientists everywhere communicate and compare results clearly
C. Because full words are considered unscientific
D. To make examinations more difficult for students
Show Answer & Explanation

Answer: (B) To create a precise, shared language that lets scientists everywhere communicate and compare results clearly

Explanation:
Assigning defined symbols and units to quantities allows ideas and measurements to be expressed unambiguously, so that scientists working in different places or languages can still understand and compare each other's work without confusion.

Question: When the chapter says predictions like how far a kicked football will travel are not guesses, what point is it making?
A. Such predictions are made randomly and happen to be lucky
B. Such predictions rest on established laws and models, so they are reasoned expectations rather than blind guesses
C. Football cannot really be predicted using science
D. Predictions in science are always exactly correct once made
Show Answer & Explanation

Answer: (B) Such predictions rest on established laws and models, so they are reasoned expectations rather than blind guesses

Explanation:
The text stresses that once laws, theories and models are well established, they let us reasonably anticipate outcomes such as a ball's flight, based on evidence and careful thinking. This is different from casual guessing, though the chapter also notes predictions can be revised if they turn out wrong.

Question: The chapter's estimate of daily air intake used two separate approaches, breath-counting and balloon-filling rate, that gave close but not identical answers. What does this best demonstrate?
A. Estimation is a useless skill in science
B. Getting a rough but reasonable figure, rather than an exact one, is often enough to judge if a result makes sense
C. Only one estimation method should ever be trusted
D. Breathing rate is impossible to measure in any way
Show Answer & Explanation

Answer: (C) Only one estimation method should ever be trusted

Explanation:
• Two independent estimates (about 10,000 litres and about 8,640 litres) were compared
• Both fell in a similar range, supporting the answer's reasonableness
• The chapter uses this to show estimation builds confidence and checks intuition, not that any single number is exact

Question: Toward the end of the chapter, science is described as more than facts and experiments. What additional quality is highlighted as central to it?
A. Science is mainly a competition between individual scientists
B. Science is a human activity built on curiosity, creativity, collaboration and questioning across generations
C. Science is only useful for those who study it beyond Grade 10
D. Science progresses without ever needing to be revised
Show Answer & Explanation

Answer: (B) Science is a human activity built on curiosity, creativity, collaboration and questioning across generations

Explanation:
The closing part of the chapter frames science as something people build together over time by asking questions, testing ideas, sharing results and learning from mistakes, and notes that this scientific way of thinking remains valuable even for those who do not pursue science further.

Free study material for Science

Multiple Choice Questions (MCQs) for Class 9 Science Chapter 02 Cell The Building Block Of Life

Chapter MCQs with Answers for Class 9 Science

Review structured objective questions for Class 9 Science Chapter 02 Cell The Building Block Of Life. Built according to official CBSE guidelines, these MCQ sets support daily revision and core concept reinforcement.

Expert Practice Material for Class 9 Science

Each question includes structured solution keys mapped directly to standard CBSE textbooks, helping students evaluate their reasoning and correct mistakes early in their revision.

Complete Your Chapter Revision

Wrap up your chapter revision by testing your knowledge against standard question formats. Everything on our platform is provided free of charge.

FAQs

Where can I access latest CBSE Class 9 Science Chapter 02 Cell The Building Block Of Life MCQs Set 01?

You can get most exhaustive CBSE Class 9 Science Chapter 02 Cell The Building Block Of Life MCQs Set 01 for free on StudiesToday.com. These MCQs for Class 9 Science are updated for the 2026-27 academic session as per CBSE examination standards.

Are Assertion-Reasoning and Case-Study MCQs included in the Science Class 9 material?

Yes, our CBSE Class 9 Science Chapter 02 Cell The Building Block Of Life MCQs Set 01 include the latest type of questions, such as Assertion-Reasoning and Case-based MCQs. 50% of the CBSE paper is now competency-based.

How do practicing Science MCQs help in scoring full marks in Class 9 exams?

By solving our CBSE Class 9 Science Chapter 02 Cell The Building Block Of Life MCQs Set 01, Class 9 students can improve their accuracy and speed which is important as objective questions provide a chance to secure 100% marks in the Science.

Do you provide answers and explanations for CBSE Class 9 Science Chapter 02 Cell The Building Block Of Life MCQs Set 01?

Yes, Science MCQs for Class 9 have answer key and brief explanations to help students understand logic behind the correct option as its important for 2026 competency-focused CBSE exams.

Can I practice these Science Class 9 MCQs online?

Yes, you can also access online interactive tests for CBSE Class 9 Science Chapter 02 Cell The Building Block Of Life MCQs Set 01 on StudiesToday.com as they provide instant answers and score to help you track your progress in Science.