CBSE Class 7 Science Chapter 10: Life Processes in Plants — Assertion & Reason
CBSE Class 7 Science Assertion & Reason
Expert crafted · Instant PDF download · 2026-27
The following Assertion and Reason questions are based on Chapter 10: Life Processes in Plants from the NCERT Class 7 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): Plants require both sunlight and water for proper growth and development.
Reason (R): Without water, plants wilt, and without sunlight, they cannot produce the food necessary for growth.
Reason (R): Without water, plants wilt, and without sunlight, they cannot produce the food necessary for growth.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Sunlight and water are fundamental raw materials required by plants to carry out their life processes and increase in size.
2
Assertion (A): Leaves are often referred to as the 'food factories' of plants.
Reason (R): The synthesis of food in plants primarily occurs in the leaves through a process called photosynthesis.
Reason (R): The synthesis of food in plants primarily occurs in the leaves through a process called photosynthesis.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Because the vast majority of a plant's food production happens within the flat, broad structure of its leaves, they act as natural factories.
3
Assertion (A): Most leaves appear green in colour.
Reason (R): Leaves contain a green pigment called chlorophyll which helps in capturing sunlight efficiently.
Reason (R): Leaves contain a green pigment called chlorophyll which helps in capturing sunlight efficiently.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. The presence of the chlorophyll pigment is what gives leaves their characteristic green hue and allows them to absorb light energy.
4
Assertion (A): Before testing a leaf for starch with iodine, it is boiled in water and then dipped in hot alcohol.
Reason (R): Boiling in alcohol decolourises the leaf by removing chlorophyll, making it easier to observe the colour change.
Reason (R): Boiling in alcohol decolourises the leaf by removing chlorophyll, making it easier to observe the colour change.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Removing the strong green pigment ensures that the blue-black colour of the iodine-starch reaction is clearly visible.
5
Assertion (A): Heating a test tube containing alcohol directly over a spirit lamp flame is a safe laboratory practice.
Reason (R): Alcohol is highly flammable and can easily catch fire, causing burns.
Reason (R): Alcohol is highly flammable and can easily catch fire, causing burns.
Answer: (d)
A is false, but R is true. Alcohol should never be heated directly over a flame due to its highly flammable nature; it must be heated safely using a water bath.
6
Assertion (A): A plant kept in a completely dark room for several days will still continue to produce starch in its leaves.
Reason (R): Sunlight is absolutely essential for the process of photosynthesis to take place.
Reason (R): Sunlight is absolutely essential for the process of photosynthesis to take place.
Answer: (d)
A is false, but R is true. Without sunlight, the plant cannot perform photosynthesis, meaning it will stop producing starch and eventually use up its stored reserves.
7
Assertion (A): A destarched leaf kept inside a bottle containing caustic soda does not turn blue-black when tested with iodine.
Reason (R): Caustic soda absorbs carbon dioxide from the air, proving that carbon dioxide is essential for starch preparation.
Reason (R): Caustic soda absorbs carbon dioxide from the air, proving that carbon dioxide is essential for starch preparation.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Because the caustic soda removes CO2, the trapped part of the leaf cannot perform photosynthesis, resulting in a negative starch test.
8
Assertion (A): During photosynthesis, plants produce glucose and release carbon dioxide gas into the air.
Reason (R): The process of photosynthesis uses carbon dioxide and water to produce glucose and oxygen.
Reason (R): The process of photosynthesis uses carbon dioxide and water to produce glucose and oxygen.
Answer: (d)
A is false, but R is true. Plants release oxygen during photosynthesis, not carbon dioxide. They take in carbon dioxide to make glucose.
9
Assertion (A): The glucose produced during photosynthesis is often converted into starch for storage in plants.
Reason (R): Glucose is a complex carbohydrate that cannot be used directly for energy.
Reason (R): Glucose is a complex carbohydrate that cannot be used directly for energy.
Answer: (c)
A is true, but R is false. Plants do convert glucose to starch for storage, but glucose is actually a simple carbohydrate that serves as an instant source of energy.
10
Assertion (A): Leaves that appear red, violet, or brown cannot perform photosynthesis at all.
Reason (R): These leaves contain large amounts of other coloured pigments that hide the green chlorophyll, but they still perform photosynthesis.
Reason (R): These leaves contain large amounts of other coloured pigments that hide the green chlorophyll, but they still perform photosynthesis.
Answer: (d)
A is false, but R is true. Non-green leaves do possess chlorophyll; it is simply masked by other pigments. They are fully capable of carrying out photosynthesis.
11
Assertion (A): Stomata are essential for the survival and normal functioning of a plant.
Reason (R): Stomata help in the exchange of oxygen and carbon dioxide during photosynthesis and respiration.
Reason (R): Stomata help in the exchange of oxygen and carbon dioxide during photosynthesis and respiration.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. These tiny pores on the leaf surface act as the plant's breathing system, facilitating the crucial exchange of gases.
12
Assertion (A): When a plant twig with white flowers is placed in water mixed with red ink, the stem and flowers turn red after some time.
Reason (R): Water and dissolved minerals move upwards through thin tube-like structures called the xylem.
Reason (R): Water and dissolved minerals move upwards through thin tube-like structures called the xylem.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. The xylem tissue actively transports the red-coloured water from the base up into the stem, leaves, and flowers.
13
Assertion (A): The food prepared by the leaves is transported to all other parts of the plant through the xylem.
Reason (R): Phloem is a set of thin tube-like structures responsible for the transport of food in plants.
Reason (R): Phloem is a set of thin tube-like structures responsible for the transport of food in plants.
Answer: (d)
A is false, but R is true. Food is transported by the phloem, not the xylem. The xylem is strictly responsible for transporting water and minerals.
14
Assertion (A): Minerals present in the soil are completely useless for the growth of plants.
Reason (R): Water and minerals are taken up by the roots and transported upwards to perform various functions.
Reason (R): Water and minerals are taken up by the roots and transported upwards to perform various functions.
Answer: (d)
A is false, but R is true. Minerals are highly important nutrients for plant growth and are absorbed alongside water by the root system.
15
Assertion (A): Just like animals, plants also respire to release energy for their growth and development.
Reason (R): During respiration, glucose is broken down in the presence of oxygen to release carbon dioxide, water, and energy.
Reason (R): During respiration, glucose is broken down in the presence of oxygen to release carbon dioxide, water, and energy.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Respiration is a universal life process. Plants must break down the glucose they produce to access the usable energy needed to survive.
16
Assertion (A): Plants carry out respiration only during the night when there is no sunlight.
Reason (R): All parts of a plant, whether green or non-green, carry out respiration continuously to obtain usable energy.
Reason (R): All parts of a plant, whether green or non-green, carry out respiration continuously to obtain usable energy.
Answer: (d)
A is false, but R is true. Respiration is a continuous, 24/7 process in plants, independent of sunlight, unlike photosynthesis which only occurs during the day.
17
Assertion (A): Germinating seeds kept in a closed flask produce a gas that turns lime water milky.
Reason (R): Germinating seeds respire actively and release carbon dioxide, which reacts with lime water to make it milky.
Reason (R): Germinating seeds respire actively and release carbon dioxide, which reacts with lime water to make it milky.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. As the seeds grow, they consume oxygen and release carbon dioxide through respiration, causing the classic milky chemical reaction in lime water.
18
Assertion (A): Photosynthesis and respiration are two opposing processes in terms of gas exchange in plants.
Reason (R): Photosynthesis uses carbon dioxide and releases oxygen, whereas respiration uses oxygen and releases carbon dioxide.
Reason (R): Photosynthesis uses carbon dioxide and releases oxygen, whereas respiration uses oxygen and releases carbon dioxide.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. The raw materials of one process are the products of the other, creating a perfect balance of gas exchange within the plant.
19
Assertion (A): A plant in a completely sealed, transparent bottle (a bottle garden) can survive for a very long time.
Reason (R): The plant uses the oxygen produced in photosynthesis for respiration, and the carbon dioxide produced in respiration for photosynthesis.
Reason (R): The plant uses the oxygen produced in photosynthesis for respiration, and the carbon dioxide produced in respiration for photosynthesis.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. A sealed bottle garden acts as a self-sustaining miniature ecosystem where the gases recycle perfectly between the two life processes.
20
Assertion (A): Respiration is a process that synthesises complex food, while photosynthesis breaks it down.
Reason (R): Photosynthesis is the synthesis of food (glucose), while respiration is the breaking down of glucose to release energy.
Reason (R): Photosynthesis is the synthesis of food (glucose), while respiration is the breaking down of glucose to release energy.
Answer: (d)
A is false, but R is true. The assertion has the definitions swapped. Photosynthesis builds food (glucose), and respiration breaks that food down.
❓ Frequently Asked Questions
What is covered in CBSE Class 7 Science Chapter 10 Life Processes in Plants?
This chapter covers all key topics from Life Processes in Plants as per CBSE 2026-27 syllabus.
Is this Assertion & Reason useful for CBSE board exams?
Yes, designed for CBSE Class 7 board exam preparation covering the complete syllabus.
Are these CBSE Class 7 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 7 Science?
All chapters of CBSE Class 7 Science are covered at eBookPublisher with free Assertion & Reason for each chapter.
Can I study Life Processes in Plants online for free?
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