CBSE Class 7 Curiosity: Curiosity – Takshila-DPS Pune- Patna-Coimbatore

AUTHOR

Dr. Gauri Kshirsagar

MBBS, DNB (DVL)

Dermatologist, Cosmetologist and Laser Surgeon

Nuleaf Skin Clinic and Hair Transplant Center, Undri, Pune

www.nuleafhair.com

As a mother of twin daughters and a Consultant Dermatologist based in Undri, Pune, life is always a balancing act. Between busy clinic hours, parenting duties, and everyday chaos, I’ve been creating study notes since Class 4 to help my girls understand and revise their lessons better. Over the years, these weekend study sessions turned into a special tradition—discussing topics taught in school and turning them into organized, easy-to-revise notes.

The notes I’m sharing here are from the 2025–26 academic year of DPS Pune – Patna – Coimbatore, and cover Class 7 chapters. They include all the key points that are likely to be asked in exams, compiled from the Class7 Curiosity Textbook , school study materials, class notes and school revision sheets.

Each page was made with care, love, and a hope to make learning feel a little easier—especially during exam time. If they help your child too, then this effort finds even more meaning.

If you find these notes useful, I’d love to hear from you in the comments section. And if you’d like me to upload notes on any particular topic from Class 6, feel free to send in your suggestions.
Don’t forget to subscribe to my blog for new updates, notes, and posts.

Wishing you and your child a wonderful academic year ahead!

Warmly,
Gauri
Mom to twins

IMPORTANT POINTS

Important points:

1. As animals grow, their size and weight usually increase, and their bodies undergo various changes. 
2. Food provides nutrients like carbohydrates, fats, proteins, vitamins, and minerals, which, along with water, are all essential for growth.
3. All living organisms require food that provide energy for their growth and development.
4. Plants use carbon dioxide and water in the presence of sunlight and chlorophyll to produce glucose and oxygen. This process of synthesis of food is known as photosynthesis.
5. Leaves are the ̒ food factories ̓ of a plant.
6. Tiny pores on the surface of leaves, called stomata, help in the exchange of oxygen and carbon dioxide during photosynthesis and respiration.
7. The xylem transports water and minerals from roots, while the phloem carries food from leaves to all parts of the plants.
8. Plants break down glucose and release energy by a process called respiration. They use oxygen and release carbon dioxide in this process.

How Do Plants Grow?

Growth in Plants: Plants grow by producing new leaves, flowers, branches, and increasing in height and girth (Stem).

Growth is influenced by:

1. Water – essential for transporting nutrients and photosynthesis.
2. Sunlight – provides energy for making food.
3. Air (carbon dioxide) – taken in from the atmosphere for food synthesis.

Plants that receive both water and sunlight show healthy growth. Lack of either one affects growth.

ACTIVITY 1: Effect of Sunlight and Water on Plant Growth

How to do the activity:

1. Take 3 earthen pots or containers of the same size filled with garden soil.
2. Plant similar-sized saplings of a fast-growing plant like chilli or tomato in each pot.
3. Label the pots as A, B, and C.
4. Count and record the number of leaves on each sapling.
5. Place the pots as follows:
   1. Pot A: In sunlight, water it daily to keep the soil moist.
   1. Pot B: In sunlight, but do not water.
   1. Pot C: In a dark place, water it daily to keep the soil moist.
6. Observe the plants daily for 2 weeks.

Observation:

• Record the height, number of leaves, colour of leaves (green/yellow), and any other visible changes in all three pots.
• You may observe the following:
  • Pot A: Plant grows well, with more leaves and healthy green colour.
  • Pot B: Plant may wilt or die due to lack of water.
  • Pot C: Plant shows less growth and pale leaves due to lack of sunlight.

Analysis:

1. The plant in Pot A, kept in direct sunlight with adequate water, grows better than the plant in Pot C, which gets adequate water but no sunlight.
2. The plant in Pot B may have died as it did not get water even though it received adequate sunlight.

• The plant in Pot A shows maximum growth.
• The plant in Pot B shows least or no growth.
• Without water (Pot B), plants cannot survive even if sunlight is available.
• Without sunlight (Pot C), plants grow poorly even if water is available.

Conclusion: This shows that plants need both sunlight and water for healthy growth.

FASCINATING FACTS

Quote from Vrikshayurveda

“Trees do not produce fruits and flowers merely because they are planted.”
— Vrikshayurveda (Ancient Indian text)

About Vrikshayurveda

Definition:

• Vrikshayurveda is an ancient Indian text focused on plant science and agriculture.
• It contains practical knowledge about:
  • Plant growth
  • Soil types
  • Agricultural practices

Purpose of the Text

1. Aimed to improve crop health, growth, and production.
2. Based on observations and experiences collected over time.
3. Ideas systematically documented to guide farmers.

Use of Organic Manure

• Mentions different methods of organic manure preparation.
• Example: Mixing water, barley, and seeds like:
  • Green gram (moong)
  • Black gram (urad)
  • Horse gram (kulthi)

How Do Plants Get Food for their Growth?

1. Animals get their food from plants, either directly by eating plants or indirectly by eating animals that in turn eat plants for their nutrition and growth.
2. Unlike animals, plants do not eat food.

Why are Leaves called the ̒ food factories̓ of plants?

Ans)

1. Plants store food in the form of starch, a type of carbohydrate.
2. This starch is produced in the leaves of a plant which, by design, are generally broad and flat.
3. These are mostly green because of the presence of a green pigment called chlorophyll, that helps in capturing sunlight efficiently

ACTIVITY 2: Role of Chlorophyll in the preparation of food (starch) in plants.

How to do the activity:

1. Take a green leaf and boil it in water for 5 minutes to soften it.
2. Put the leaf into a test tube containing alcohol.
3. Place the test tube in a beaker of boiling water.
4. Wait until the leaf becomes colourless.
5. Carefully take the leaf out and place it on a plate.
6. Using a dropper, add a few drops of diluted iodine solution to the decolourised leaf.
7. Wait and observe any colour change.

⚠️ Caution: Never heat alcohol directly on a flame. It is highly flammable and can cause fire or burns.

Observation:

If the leaf turns blue-black, it confirms the presence of starch.

Analysis:

1. Decolourisation of a leaf enables us to easily observe colour change and, thus, the presence of starch.
2. The blue-black colour indicates that starch is present in the leaf. This means that green leaves store food in the form of starch.
3. From Activity 1, we know that sunlight and water are essential for plant growth.

Conclusion: This activity shows that green leaves store starch as food.

ACTIVITY 3: Role of sunlight in the production of food in the form of starch in plants.

How to do the activity:

1. Take two similar potted plants and keep:
   1. One plant in sunlight
   1. The other plant in darkness for 36 hours
2. From each plant, take a leaf that has both green and non-green patches.
3. Using tracing paper, make a sketch of the green and non-green areas on both leaves before testing.
4. Perform the iodine starch test (as done in Activity 2) on both leaves.

Observation:

1. Leaf from the plant kept in sunlight:
   1. Green patches turn blue-black (starch is present).
   1. Non-green patches do not change colour (no starch).
2. Leaf from the plant kept in darkness: No part turns blue-black, not even the green patches (no starch produced).

Analysis:

1. Leaf from the plant kept in sunlight:
2. Chlorophyll (present in green patches) is essential to make starch.
3. Non-green patches lack chlorophyll, so they cannot produce starch.
4. Leaf from the plant kept in darkness:

Leaves kept in the dark do not produce starch, even if they are green, hence chlorophyll alone is not enough—sunlight is also needed.

Conclusion: Both chlorophyll and sunlight are necessary for plants to make their food. Therefore, leaves are rightly called “food factories” of plants.

FASCINATING FACTS

Why do some plant leaves appear red, violet, or brown?

Ans)

1. Some plant leaves appear red, violet, or brown because they contain more of these coloured pigments than the green-coloured chlorophyll.
2. This hides the green colour.  
3. Some of these pigments also help in photosynthesis.
4. An iodine test can check for the presence of starch in these leaves, indicating that photosynthesis has indeed taken place.

Role of air in the preparation of food

ACTIVITY 4: Role of Carbon Dioxide in Making Food

How to do the activity:

1. Take a potted green plant and keep it in darkness for 2–3 days to allow it to destarch (i.e., lose any stored starch).
2. Select one leaf from this plant for the experiment.
3. Pour caustic soda (sodium hydroxide) into a wide-mouthed bottle.
   1. Caustic soda absorbs carbon dioxide from the air.
   1. ⚠️ Caution: Caustic soda is a strong chemical that can cause skin burns; only teachers should handle it.
4. Insert half of the destarched leaf into the bottle through a split cork, keeping the other half outside the bottle.
5. Place the setup in sunlight for a few hours.
6. After some time, remove the leaf and perform the iodine test on it (as done in Activity 2).
7. Record your findings.

Observation:

1. The part of the leaf outside the bottle turns blue-black (shows presence of starch).
2. The part of the leaf inside the bottle does not change colour (no starch present).

Analysis:

1. The leaf part inside the bottle did not make food because carbon dioxide was removed by the caustic soda.
2. The part outside the bottle had access to carbon dioxide and made starch.

Conclusion: This shows that carbon dioxide from air is essential for the preparation of food in plants.

ACTIVITY 5: Release of Oxygen During Photosynthesis

How to do the activity:

1. Take two identical set-ups (as shown in Fig. 10.4) with:
   1. A water plant (like Hydrilla) placed under a funnel in a beaker of water.
   1. An inverted test tube over the funnel to collect gas.
2. Label the set-ups as:
   1. Set-up A: Place it in sunlight.
   1. Set-up B: Place it in darkness.
3. Observe both set-ups after a few hours.

Observation:

1. In Set-up A (in sunlight):
   1. Bubbles of gas are seen forming and collecting in the inverted test tube.
   1. When sufficient gas is collected:
      1. Placed a thumb on the mouth of the test tube and removed it carefully.
      1. Inserted a lit matchstick into the test tube.
      1. The matchstick burned brightly with an intense flame
2. In Set-up B (in darkness):
   1. No bubbles are seen.
   1. No gas is collected in the test tube.

Analysis:

• The gas released in Set-up A is oxygen.
• This confirms that oxygen is released during photosynthesis.
• Photosynthesis occurs only in the presence of sunlight.

Conclusion: This activity shows that plants give out oxygen as a byproduct of photosynthesis.

Important points:

1. Sunlight, water, chlorophyll and carbon dioxide are essential for the synthesis of food in plants. This process by which plants prepare food in the presence of sunlight and chlorophyll is called photosynthesis.
2. A leaf is the primary site for photosynthesis.
3. Other parts of the plants which have chlorophyll also perform photosynthesis.
4. Plants take in carbon dioxide from the air and water, and use sunlight to prepare their food by the process of photosynthesis.

Photosynthesis:

Photosynthesis (Defⁿ): Photosynthesis is the process by which green plants make their own food (Glucose) using sunlight, carbon dioxide (from air), and water (from soil), in the presence of chlorophyll (a green pigment in leaves). This glucose (simple carbohydrate) not only serves as an instant source of energy but also later gets converted into starch for storage. 

Carbon dioxide + Water + Sunlight → Glucose (food) + Oxygen

How do leaves exchange gases during photosynthesis?

Photosynthesis requires carbon dioxide, and oxygen is released in the process. Which part of the plant helps in the exchange of carbon dioxide and oxygen?

ACTIVITY 7: Observing Stomata on a Leaf

How to do the activity:

1. Collect a leaf from a plant like rhoeo, money plant, onion, hibiscus, coleus, or grass.
2. Place the leaf in a beaker filled with water.
3. Peel a thin layer from the lower surface of the leaf.
4. Put the peel in a watch glass containing water.
5. Take a microscope slide and place a drop of water on it.
6. Using forceps, place the leaf peel on the slide.
7. Add a drop of ink on the peel with a dropper.
8. Place a coverslip over the peel.
9. Observe under a microscope.

Observation:

1. You will see tiny pores on the surface of the peel.
2. These pores are called stomata.

Transport in Plants 

TRANSPORT OF WATER AND MINERALS

1. Plants use water in photosynthesis to make food.
2. Roots absorb water and minerals from the soil.
3. Minerals are important nutrients that help plants grow.
4. The absorbed water and minerals are transported to all parts of the plant through special tissues called xylem.

ACTIVITY 8: Movement of Water Through Xylem

How to do the activity:

1. Take two glass tumblers and label them A and B.
2. Fill one-third of each tumbler with water.
3. Add a few drops of red ink to Tumbler B.
4. Take twigs of two similar tender plants and cut their stems obliquely under water. (preferably with white-coloured flowers – for example, white sadabahar, balsam)
5. Immediately place:
   1. One plant in Tumbler A (plain water)
   1. One plant in Tumbler B (red-ink water)
6. Leave both set-ups for one day.
7. The next day, observe the stems, leaves, and flowers of both plants.
8. Cut open the stem from the upper part (not immersed in water) and examine it using a magnifying glass.

Observation:

1. Plant in Tumbler B shows red colour in:
   1. Stem
   1. Leaves
   1. Flowers
2. Plant in Tumbler A shows no colour change.
3. On cutting the stem of the plant in Tumbler B, red lines can be seen inside the stem.

Analysis:

1. The red ink travels up through the xylem, a thin, tube-like structure present in:
   1. Stems
   1. Branches
   1. Leaves
2. This shows that xylem helps in transporting water and dissolved minerals from roots to all parts of the plant.
3. The visible red colour confirms the upward movement of substances through xylem.

Conclusion: water and minerals are transported to the leaves and other parts of plants through the xylem

TRANSPORT OF FOOD

1. Leaves are the main site of photosynthesis where food is prepared.
2. This food is then transported to all parts of the plant.
3. The transport of food happens through phloem, a set of thin, tube-like structures present in plants.
4. The phloem carries food from the leaves to:
   1. Growing parts (like shoots and roots)
   1. Storage organs (like seeds and roots)

Remember:

1. Xylem = Transports water and minerals from roots to leaves
2. Phloem = Transports food from leaves to other parts of the plant

Difference Between Xylem and Phloem

	Feature	Xylem	Phloem
	Function	Transports water and minerals	Transports food
	Tube Structure	Long, narrow, thick-walled tubes	Long, thin, soft-walled tubes
	Direction of Transport	Upward only (unidirectional) from roots to leaves &other aerial parts of the plant.	Both upward and downward (bidirectional) from leaves (source) to different parts of the plant.
	Type of Transport	Inorganic substances (water, minerals)	Organic substances (food like glucose)
	Tissue Type	Mostly made of dead cells	Mostly made of living cells

Do Plants Respire?

ACTIVITY 9: Testing Respiration in Plants

How to do the activity:

1. Soak some moong seeds in water overnight.
2. Put a layer of moist cotton inside a conical flask.
3. Place the soaked seeds on the cotton in the flask.
4. Close the mouth of the flask with a cork having two holes.
5. Insert two glass tubes (A and B) into the holes, as shown in Fig. 10.9.
6. Leave the setup undisturbed in the dark for 24 hours.
7. Take two test tubes and fill them with lime water.
8. Seal one test tube with a cork having one hole and insert a glass tube through it.
9. Connect the glass tube from the flask to the lime water test tube using a rubber pipe.
10. Compare the lime water in both test tubes after some time.

Observation:

1. The lime water in the connected test tube turns milky.
2. The other test tube (not connected) shows no change.

Analysis:

1. Lime water turns milky because of carbon dioxide released by seeds during respiration.
2. The seeds use oxygen to break down glucose and release carbon dioxide, water, and energy.
3. The carbon dioxide travels through the tube and reacts with lime water, making it milky.

Word Equation for Respiration:

Glucose + Oxygen → Carbon dioxide + Water + Energy

C_6​H₁₂​O₆​ + 6O₂​ → 6CO₂ ​+ 6H₂​O + Energy (ATP – Adenosine Triphosphate)

Conclusion:

1. All parts of a plant, green or non-green, carry out respiration.
2. Plants use the energy released during respiration for growth and development.
3. This shows that plants have systems for making, transporting, and using food to get energy.

Analysis:

1. Stomata are tiny openings on the surface of leaves.
2. They help in the exchange of gases (like oxygen and carbon dioxide).
3. Stomata play an important role in photosynthesis and respiration in plants.

Know a Scientist

Rustom Hormusji Dastur

1. Rustom Hormusji Dastur (1896–1961) was an Indian plant scientist.
2. He worked as the Head of the Botany Department at the Royal Institute of Science, Bombay (now Institute of Science, Mumbai) from 1921 to 1935.
3. He studied the process of photosynthesis in detail.
4. His research focused on:
   1. Effect of water on photosynthesis
   1. Role of temperature
   1. Importance of colour of light
5. His work helped improve the scientific understanding of photosynthesis in India.

Kamala Sohonie

1. Kamala Sohonie (1911–1998) was a pioneering woman scientist of India.
2. She was the first Indian woman to receive a Ph.D. in science from Cambridge University.
3. Her Ph.D. research focused on respiration in plants.
4. After returning to India, she worked at:
   1. Lady Hardinge Medical College, New Delhi
   1. Nutrition Research Laboratory, Coonoor
   1. Later, she joined the Royal Institute of Science, Bombay and became its Director.
5. Her work helped improve the nutritive value of plant-based foods.
6. She also researched the sap of the coconut palm, promoting it as a healthy drink called Neera.

Terms & Definitions

1. Photosynthesis:Photosynthesis is the process by which green plants make their own food (Glucose) using sunlight, carbon dioxide (from air), and water (from soil), in the presence of chlorophyll (a green pigment in leaves). This glucose (simple carbohydrate) not only serves as an instant source of energy but also later gets converted into starch for storage. 
2. Chlorophyll: A green pigment in leaves that absorbs sunlight for photosynthesis.
3. Stomata: Tiny pores on the surface of leaves that help in the exchange of gases.
4. Xylem: Vascular tissue in plants that transports water and minerals from roots to leaves.
5. Phloem: Vascular tissue that transports food (glucose) from leaves to other parts of the plant.
6. Respiration: The process of breaking down glucose using oxygen to release energy, carbon dioxide, and water

SUMMARY OF THE CHAPTER (SCM)

1. Growth in Plants

1. Plants grow by producing new leaves, flowers, branches, and increasing in height and girth.
2. Growth is influenced by:
   1. Water – essential for transporting nutrients and photosynthesis.
   1. Sunlight – provides energy for making food.
   1. Air (carbon dioxide) – taken in from the atmosphere for food synthesis.
3. Plants that receive both water and sunlight show healthy growth. Lack of either one affects growth.

2. How Plants Get Their Food

1. Leaves – The Food Factories
   1. Green leaves prepare food through a process called photosynthesis.
   1. The green pigment chlorophyll in leaves captures sunlight, enabling the plant to make food.
   1. The food produced is a simple sugar called glucose, which is later converted into starch for storage.
2. Essentials for Photosynthesis: Plants need the following to carry out photosynthesis:
3. Sunlight – source of energy
4. Chlorophyll – absorbs sunlight
5. Carbon dioxide – taken in from air
6. Water – absorbed from soil
7. Role of Leaf Colour in Photosynthesis
8. Green parts of leaves contain chlorophyll and can perform photosynthesis.
9. Non-green patches (e.g., white, red) may not contain chlorophyll and may not produce starch.
10. Some leaves appear red or violet due to other pigments, but may still contain chlorophyll beneath, allowing photosynthesis.

4. Gas Exchange in Leaves

1. Stomata are tiny pores mostly on the underside of leaves.
2. They help in the exchange of gases — taking in carbon dioxide and releasing oxygen during photosynthesis.
3. During respiration, they allow oxygen in and carbon dioxide out.

5. Transport in Plants

1. Transport of Water and Minerals
2. Water and minerals are absorbed from the soil by roots.
3. They are transported upward to all parts of the plant through xylem – a network of tube-like structures.
4. Transport of Food
5. Food made in leaves is distributed to other parts of the plant through phloem – another set of tube-like tissues.
6. This process ensures all plant parts get energy and nutrients.
7. Food prepared in the leaves is transported through phloem to:
8. Growing parts (roots and shoots)
9. Storage organs (e.g., roots, seeds, fruits)

6. Respiration in Plants

1. Like all living beings, plants also respire.
2. They break down glucose in the presence of oxygen to release energy, carbon dioxide, and water.
3. Word Equation for Respiration:

Glucose + Oxygen → Carbon dioxide + Water + Energy

4. This energy is used by the plant for growth, repair, and functioning.
5. Respiration happens in all parts of a plant – both green and non-green.

SUMMARY OF KEY PROCESSES

Process	Inputs	Outputs	Main Site
Photosynthesis	CO₂, Water, Sunlight, Chlorophyll	Glucose, Oxygen	Leaves (green parts)
Respiration	Glucose, Oxygen	CO₂, Water, Energy	All plant parts
Water Transport	Water, Minerals	Delivered to all parts	Xylem tissues
Food Transport	Glucose (from leaves)	Delivered to other parts	Phloem tissues
Gas Exchange	CO₂ and O₂	In and out through stomata	Leaf surface

QUESTIONS FROM TEXTBOOKS

Q.1) Difference Between Photosynthesis and Respiration:

Feature	Photosynthesis	Respiration
Raw materials	Carbon dioxide and water	Glucose and oxygen
Products	Glucose (food) and oxygen	Carbon dioxide, water, and energy
Word equation	Carbon dioxide + Water → Glucose + Oxygen (with sunlight)	Glucose + Oxygen → Carbon dioxide + Water + Energy
Importance	Prepares food using sunlight energy	Releases energy from food for growth and other functions

Q.2) Imagine a situation where all the organisms that carry out photosynthesis on the earth have disappeared. What would be the impact of this on living organisms?

Ans) If all photosynthetic organisms vanished:

1. No oxygen would be produced.
2. Carbon dioxide would build up in the atmosphere.
3. No food would be made at the base of the food chain.
4. All living organisms, including humans, would eventually die due to lack of oxygen and food.

Q.3) A potato slice shows the presence of starch with iodine solution. Where does the starch in potatoes come from? Where is the food synthesized in the plant, and how does it reach the potato?

Ans)

1. Starch in potatoes comes from food prepared in the leaves through photosynthesis.
2. The leaves make food and it is transported to the potato (a storage organ) via the phloem.

Q.4) Does the broad and flat structure of leaves make plants more efficient for photosynthesis? Justify your answer.

Ans) Yes, the broad and flat structure of leaves:

1. Increases surface area to absorb more sunlight.
2. Allows for efficient gas exchange through stomata.
3. Helps the plant capture more light, making photosynthesis more efficient.

Q.5) X is broken down using Y to release carbon dioxide, Z, and energy.

X + Y Carbon dioxide + Z + Energy

X, Y, and Z are three different components of the process.

What do X, Y, and Z stand for?

Ans) Given:

X + Y → Carbon dioxide + Z + Energy

• X = Glucose
• Y = Oxygen
• Z = Water

Q.6) Krishna set-up an experiment with two potted plants of same size and placed one of them in sunlight and the other in a dark room, as shown in Fig. 10.10.

Answer the following questions —

(i) What idea might she be testing through this experiment?

(ii) What are the visible differences in plants in both the conditions?

(iii) According to you, leaves of which plants confirm the iodine test for

Ans)

(i) What idea is she testing?

• Whether sunlight is necessary for photosynthesis and starch formation.

(ii) Visible differences:

• Sunlight plant: Healthy, green, normal growth.
• Dark plant: Weak, pale, yellowing leaves, no growth.

(iii) Leaves that confirm iodine test for starch:

• (a) Sunlight – Yes (starch present).
• (b) Dark – No (starch not formed).

Q.7) Vani believes that ‘carbon dioxide is essential for photosynthesis’. She puts an experimental set-up, as shown in Fig. 10.11, to collect evidence to support or reject her idea.

Answer the following questions —

(i) In which plant(s) in the above set-up(s) will starch be formed?

(ii) In which plant(s) in the above set-up(s) will starch not be formed?

(iii) In which plant(s) in the above set-up(s) will oxygen be generated?

(iv) In which plant(s) in the above set-up(s) will oxygennot be generated?

Ans)

(i) Starch will be formed in:

• (a) Sunlight with CO₂

(ii) Starch will not be formed in:

• (b) Sunlight without CO₂
• (c) Dark with CO₂
• (d) Dark without CO₂

(iii) Oxygen will be generated in:

• (a) Sunlight with CO₂

(iv) Oxygen will not be generated in:

• (b), (c), and (d)

Q.8) Ananya took four test tubes and filled three-fourth of each test tube with water. She labelled them A, B, C, and D (Fig. 10.12). In test tube A, she kept a snail; in test tube B, she kept a water plant; in test tube C, she kept both a snail and a plant. In test tube D, she kept only water. Ananya added a carbon dioxide indicator to all the test tubes. She recorded the initial colour of water and observed if there are any colour changes in the test tubes after 2–3 hours. What do you think she wants to find out? How will she know if she is correct?

Ans) Aim: To check how plants and animals affect CO₂ levels in water.

Expected Results:

Test Tube	Contents	Change in CO₂ indicator
A	Snail only	CO₂ increases (indicator changes)
B	Plant only	CO₂ decreases (due to photosynthesis)
C	Snail + Plant	Balanced – less change
D	Water only	No change

Conclusion:

• Animals release CO₂, plants absorb CO₂.
• When both are together, they balance each other.

Q.9) Design an experiment to observe if water transportation in plants is quicker in warm or cold conditions.

Ans)

Materials: Two similar potted plants, warm room, cold room, red ink, beakers

Steps:

1. Fill beakers with water and red ink.
2. Place one plant in warm condition, the other in cold condition.
3. After few hours, observe how far the red ink has travelled up the stem.

Observation: Red ink moves faster in warm conditions.

Conclusion: Water transport is quicker in warm conditions.

Q. 10) Photosynthesis and respiration are essential to maintain balance in nature. Discuss.

Ans)

Balance

1. Photosynthesis:
   1. Takes in CO₂, releases O₂.
   1. Prepares food using sunlight.
2. Respiration:
   1. Takes in O₂, releases CO₂.
   1. Breaks down food to release energy.

Plants maintain the balance of gases in nature. Without either process, life on Earth would not be possible.

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