Exercise Solutions Available
Step-by-step answers for all textbook questions in this chapter
The Living World of Plants — Exercise Solutions
Use this page alongside the official Samacheer Kalvi textbook. Solve every exercise question on your own first, then check the solutions below.
I. Multiple Choice Questions (MCQs)
Q1. Pond is an example of ___ ecosystem.
- (a) Marine
- (b) Freshwater
- (c) Deserts
- (d) Mountain
Ponds, lakes, and rivers contain fresh water, so they belong to the freshwater ecosystem.
Q2. The important function of stomata is ___.
- (a) Conduction
- (b) Transpiration
- (c) Photosynthesis
- (d) Absorption
Stomata are tiny pores on the lower surface of leaves that allow carbon dioxide to enter for photosynthesis and oxygen to exit. They also help in transpiration, but their primary function in the textbook context is linked to photosynthesis.
Q3. Organ of absorption is ___.
- (a) Root
- (b) Stem
- (c) Leaf
- (d) Flower
Roots absorb water and minerals from the soil and conduct them upward to the stem and leaves.
Q4. The habitat of water hyacinth is ___.
- (a) Aquatic
- (b) Terrestrial
- (c) Desert
- (d) Mountain
Water hyacinth is a free-floating aquatic plant found in freshwater bodies like ponds and lakes.
Q5. ___ is a natural science concerned with the study of life and living organisms.
- (a) Chemistry
- (b) Biology
- (c) Zoology
- (d) Physics
Q6. The part of a stem from where a leaf arises is called ___.
- (a) Node
- (b) Internode
- (c) Terminal bud
- (d) Lateral bud
A node is the point on the stem where a leaf or branch arises. The region between two nodes is called an internode.
Q7. Main axis of the shoot system is called ___.
- (a) Stem
- (b) Root
- (c) Leaf
- (d) Buds
The stem is the main axis of the shoot system. It supports branches, leaves, flowers, and fruits.
Q8. The green colour of the leaf is due to the presence of ___.
- (a) Chlorenchyma
- (b) Chlorophyll
- (c) Lamina
- (d) Stomata
Chlorophyll is the green pigment present in leaves that captures sunlight for photosynthesis.
Q9. World Habitat Day is observed on the first Monday of ___.
- (a) October
- (b) November
- (c) September
- (d) December
Q10. ___ is one of the fastest-growing plants during the active growth phase.
- (a) Mango
- (b) Neem
- (c) Hibiscus
- (d) Bamboo
Bamboo can grow up to several centimetres per hour during its active growth phase, making it one of the fastest-growing plants.
Q11. ___ is the longest river in the world.
- (a) Sutlej
- (b) Yellow
- (c) The Nile
- (d) Congo
The Nile River in Africa is approximately 6,650 km long, making it the longest river in the world.
Q12. Length of the Nile river is ___.
- (a) 6560 km
- (b) 6650 km
- (c) 6506 km
- (d) 5606 km
Q13. Air spaces in stems and petioles of ___ plant are useful for floating in water.
- (a) Lotus
- (b) Water lily
- (c) Water hyacinth
- (d) Agave
Lotus stems and petioles have air chambers that help the plant float on the surface of water.
Q14. The first land plants are ___.
- (a) Neem and pine
- (b) Hibiscus and lotus
- (c) Banyan and peepal
- (d) Mosses and liverworts
Mosses and liverworts (bryophytes) were among the earliest plants to colonise land.
Q15. The ___ forest in South America produces half of the world's oxygen supply.
- (a) Taiga
- (b) Congo rain
- (c) Amazon rain
- (d) Dry deciduous
The Amazon rainforest, often called the "lungs of the Earth," produces a significant portion of the world's oxygen.
II. True or False (with Corrections)
Q1. Plants can live without water.
Correction: Plants cannot live without water. Water is essential for photosynthesis, transport of nutrients, and maintaining turgor pressure.
Q2. All plants have chlorophyll.
All green plants contain chlorophyll, which is necessary for photosynthesis. Even non-green parasitic plants like Cuscuta derive from ancestors that had chlorophyll.
Q3. Plants have three parts: the root, the stem and leaves.
Correction: Plants have several parts — root, stem, leaves, flowers, fruits, and seeds — not just three.
Q4. Mountain is an example of a freshwater habitat.
Correction: Mountain is an example of a terrestrial habitat. Rivers, ponds, and lakes are examples of freshwater habitats.
Q5. Root is modified into spines.
Correction: Leaves are modified into spines (e.g., in cactus and opuntia), not roots.
Q6. Green plants need sunlight.
Sunlight is essential for photosynthesis — the process by which green plants prepare their food.
Q7. The living world comprises plants and animals.
Q8. Root has nodes and internodes.
Correction: The stem has nodes and internodes. Roots do not possess nodes or internodes; instead, they have a root cap at the tip.
Q9. Taproot consists of a cluster of roots arising from the base of the stem.
Correction: A fibrous root system consists of a cluster of roots arising from the base of the stem. A taproot has one main root with lateral branches.
Q10. The buds at the axils of the leaves are called terminal buds.
Correction: The buds at the axils of the leaves are called axillary buds (or lateral buds). Terminal buds are found at the tip of the stem.
Q11. In the case of sugarcane, food is stored in the stem region.
Sugarcane stores sugar (sucrose) in its stem, which is why we crush the stem to extract juice.
Q12. The longest river in India is the Ganges.
The Ganges is approximately 2,525 km long, making it the longest river in India.
Q13. The Amazon rain forest in Canada produces half of the world's oxygen supply.
Correction: The Amazon rainforest is in South America, not Canada. It produces a significant portion of the world's oxygen.
III. Fill in the Blanks
IV. Match the Following
| # | Column A | Column B | Match |
|---|---|---|---|
| 1 | Tap root | (a) Grass | (c) Neem |
| 2 | Aquatic plant | (b) Teak tree | (e) Water lily |
| 3 | Desert plant | (c) Neem | (d) Opuntia |
| 4 | Grassland | (d) Opuntia | (a) Grass |
| 5 | Terrestrial plant | (e) Water lily | (b) Teak tree |
V. Arrange in Correct Sequence
Q1. Leaves — Stem — Root — Flower
The plant grows from root (below ground) upward through the stem, producing leaves first, then flowers.
Q2. Transpiration — Conduction — Absorption — Fixation
The root first fixes the plant to the soil, then absorbs water and minerals, the stem conducts them upward, and finally excess water is lost through transpiration from leaves.
VI. Very Short Answer Questions
Q1. Classify the plants on the basis of their habitats.
- Aquatic habitat — further divided into Freshwater (ponds, lakes, rivers) and Marine water (seas, oceans).
- Terrestrial habitat — further divided into Forest, Grassland, and Desert habitats.
Q2. Identify the desert plant from the following: Cactus, Hydrilla, Mango, and Rose.
Cactus grows in deserts and has adaptations like spines instead of leaves and a thick stem that stores water.
Q3. Define the term habitat.
Q4. Relate the terms leaves and photosynthesis.
VII. Short Answer Questions
Q1. Why is the jasmine plant called a twiner?
Q2. Compare the taproot and fibrous root systems.
| Feature | Taproot System | Fibrous Root System |
|---|---|---|
| Structure | One main thick root with smaller lateral roots | Cluster of thin roots of similar size |
| Origin | Grows from the radicle of the embryo | Arises from the base of the stem |
| Depth | Grows deep into the soil | Spreads shallowly in the soil |
| Examples | Mango, neem, bean, carrot | Grass, paddy, maize, banana |
| Found in | Dicotyledonous plants | Monocotyledonous plants |
Q3. Distinguish between terrestrial and aquatic habitats.
| Feature | Terrestrial Habitat | Aquatic Habitat |
|---|---|---|
| Location | On land | In water |
| Types | Forest, grassland, desert | Freshwater, marine water |
| Examples of plants | Neem, rubber tree, cactus | Lotus, water lily, marine algae |
| Water availability | Limited (varies by region) | Abundant |
| Plant adaptations | Deep roots, spines, thick cuticle | Reduced roots, air chambers for floating |
Q4. List out the plants present in your school garden.
(The actual plants in your school garden may vary. Observe and list what you see.)
Q5. What are the uses of plants?
- Food: Fruits, vegetables, grains, pulses
- Medicine: Neem, tulsi, aloe vera
- Wood/Shelter: Timber for furniture and construction
- Oxygen: Released during photosynthesis
- Clothing: Cotton from cotton plants
- Fuel: Firewood, bio-fuel
Q6. Classify plants on the basis of flowers.
- Non-flowering plants: Plants that do not produce flowers or seeds — e.g., mosses, ferns, Riccia.
- Flowering plants: Plants that produce flowers and seeds — e.g., mango, sunflower, hibiscus.
Q7. What are the properties of roots?
Q8. Write a short note on cactus.
- Stem: Thick, green, and fleshy — stores water and performs photosynthesis.
- Leaves: Modified into spines to reduce water loss through transpiration and protect from grazing animals.
- Roots: Well-developed, deep-reaching roots that absorb water from deep underground.
- Stem surface: Covered with a thick waxy layer (cuticle) to prevent water loss.
Q9. Describe the shoot system.
- Stem: The main axis that supports branches, leaves, flowers, and fruits. It has nodes and internodes.
- Leaves: Green structures that perform photosynthesis.
- Flowers: Reproductive structures.
- Fruits: Develop from flowers and contain seeds.
The shoot system grows towards sunlight (positively phototropic).
Q10. List the functions of leaves.
Q11. Classify plants on the basis of (i) flower and (ii) position of seed.
- (i) Based on flower:
- Flowering plants (e.g., mango, sunflower)
- Non-flowering plants (e.g., mosses, ferns)
- (ii) Based on position of seed:
- Gymnosperms — seeds are naked, not enclosed in a fruit (e.g., pine, cycas)
- Angiosperms — seeds are enclosed inside a fruit (e.g., mango, wheat)
Q12. List the characteristics of aquatic plants.
Q13. Give examples of freshwater and marine water habitat plants.
- Freshwater habitat plants: Water hyacinth, water lily, lotus, duckweed.
- Marine water habitat plants: Marine algae (seaweed), seagrasses, marsh grass, phytoplanktons.
Q14. Name the part modified into a tendril in Sweet Peas and Bitter Gourd.
- Sweet Peas: Leaflets are modified into tendrils.
- Bitter Gourd: Axillary buds are modified into tendrils.
Tendrils are thin, coiled structures that help weak-stemmed plants climb on support.
Q15. Define thorns.
Q16. Name the part modified into thorns/spines in Agave, Opuntia, and Bougainvillea.
- Agave: Leaf apex and margins are modified into thorns.
- Opuntia: Leaves are modified into spines.
- Bougainvillea: Stem has sharp thorns.
VIII. Complete the Analogy
1. Aerial part above ground : Shoot system :: Underground part : Root system 2. Dicotyledonous plants : Bean, Mango :: Monocotyledonous plants : Grass, paddy 3. Carrot, beetroot : store food in roots :: Sugarcane : stores food in stem 4. Photosynthesis : chlorophyll :: Transpiration : Stomata 5. Flowering plant : Sunflower :: Non-flowering plant : Riccia 6. Mango : Angiosperm :: Cycas : Gymnosperm 7. Water lily : Freshwater habitat :: Marine algae : Marine water habitat 8. Rainfall 25-200 cm : Forest habitat :: Rainfall below 25 cm : Desert habitat 9. Sweet Peas : Tendril climber :: Clitoria : Twiner 10. Leaves modified into spines : Opuntia :: Stem has sharp thorns : Bougainvillea
IX. Detailed / Long Answer Questions
Q1. Make a list of the functions of root and stem.
Functions of Root
| S.No. | Function | Description |
|---|---|---|
| 1 | Fixation | Anchors the plant firmly to the soil |
| 2 | Absorption | Absorbs water and minerals from the soil |
| 3 | Conduction | Conducts absorbed water and minerals upward to the stem |
| 4 | Storage | Some roots store food — e.g., carrot, beetroot, radish |
Functions of Stem
| S.No. | Function | Description |
|---|---|---|
| 1 | Support | Supports branches, leaves, flowers, and fruits |
| 2 | Conduction (upward) | Transports water and minerals from roots to leaves |
| 3 | Conduction (downward) | Transports prepared food from leaves to all plant parts |
| 4 | Storage | Some stems store food — e.g., sugarcane, potato, ginger |
Q2. Describe the structure of a leaf.
A leaf is a thin, flat, green structure attached to the stem. Its main parts are:
1. Leaf base — the portion that connects the leaf to the stem at the node. 2. Petiole — the stalk that joins the leaf blade to the stem. 3. Leaf lamina (blade) — the broad, flat, green portion of the leaf. 4. Midrib — the main vein running through the centre of the lamina; it gives support. 5. Veins — branch out from the midrib, forming a network that transports water and food. 6. Chlorophyll — the green pigment present in the lamina that captures sunlight for photosynthesis. 7. Stomata — tiny pores on the lower surface of the leaf for gas exchange (CO₂ in, O₂ out) and transpiration.
Q3. Explain the different types of plant habitats with examples.
Aquatic Habitat
Plants that live in water.
- Freshwater plants: Lotus, water lily, water hyacinth — found in ponds, lakes, and rivers.
- Adaptations: reduced roots, air chambers in stems for floating, broad leaves with waxy coating.
- Marine water plants: Marine algae, seagrasses — found in seas and oceans.
- Adaptations: no true roots, flexible bodies to withstand water currents.
Terrestrial Habitat
Plants that live on land.
- Forest habitat: Neem, teak, rubber tree — rainfall 25-200 cm, moderate temperature.
- Adaptations: broad leaves, deep roots, thick bark.
- Grassland habitat: Grasses, shrubs — moderate rainfall.
- Adaptations: deep roots, narrow leaves to reduce water loss.
- Desert habitat: Cactus, opuntia — rainfall below 25 cm, extreme heat.
- Adaptations: spines instead of leaves, thick fleshy stems to store water, deep roots.
- Mountain habitat: Pine, deodar — cold climate, high altitude.
- Adaptations: needle-like leaves, conical shape to shed snow, thick bark.
Q4. Describe the process of photosynthesis.
Photosynthesis is the process by which green plants prepare their own food using sunlight, carbon dioxide, and water.
Word equation: Carbon dioxide + Water + Sunlight (in the presence of chlorophyll) → Glucose + Oxygen
Conditions required: 1. Sunlight — the energy source, captured by chlorophyll. 2. Carbon dioxide — taken in through stomata from the atmosphere. 3. Water — absorbed by roots from the soil and conducted to leaves. 4. Chlorophyll — the green pigment present in leaf cells that traps light energy.
Process:
- Sunlight is trapped by chlorophyll in the leaves.
- Carbon dioxide enters the leaf through stomata.
- Water is absorbed by roots and transported to the leaf through the stem.
- Inside the leaf, carbon dioxide and water react in the presence of sunlight and chlorophyll to produce glucose (food) and oxygen.
- The glucose is used by the plant for growth and stored as starch. Oxygen is released into the air through stomata.
Why is photosynthesis important?
- It produces food for all living organisms directly or indirectly.
- It releases oxygen, which is essential for respiration.
- It maintains the balance of carbon dioxide and oxygen in the atmosphere.
Q5. Compare herbs, shrubs, and trees.
| Feature | Herbs | Shrubs | Trees |
|---|---|---|---|
| Height | Small, up to 1 metre | Medium, 1-3 metres | Tall, more than 3 metres |
| Stem | Green, soft, thin | Woody, thin but branching near base | Thick, hard, woody trunk |
| Branching | May or may not branch | Branches arise from near the base | Branches arise from the upper part (crown) |
| Lifespan | Often short-lived (1-2 seasons) | Longer lifespan | Long-lived (many years) |
| Examples | Tomato, mint, basil, wheat | Rose, hibiscus, lemon | Mango, neem, banyan |
X. HOTS (Higher Order Thinking Skills) Questions
Q. The cactus plant is green and performs photosynthesis. Which part does photosynthesis?
Q. Ginger — is it a root or a stem?
- It has nodes and internodes (root does not).
- It has scale leaves and buds at the nodes.
- It stores food (starch) — a function of some stems.
- It belongs to the plant Zingiber officinale, a tropical herb.
XI. Activity-Based Questions
Activity 1: Water Absorption by Root
Experiment: Place a carrot in water mixed with blue ink for 2-3 days. Cut it lengthwise and observe.
Observation: Blue colour appears inside the carrot, showing upward movement of water through the root.
Conclusion: Roots absorb water from the surrounding medium and conduct it upward through their tissues.
Activity 2: Conduction of Water through Stem
Experiment: Place a balsam twig in water mixed with red ink for a few hours. Observe the stem.
Observation: The stem becomes reddish as the coloured water moves upward through the xylem vessels.
Conclusion: The stem conducts water and dissolved minerals from the root upward to the leaves.
Activity 4: Story-Based Questions
1. Why did the deer feel sad? Humans chopped all the trees, destroying the deer's habitat. There was no place left to live, find food, or hide.
2. Who chopped the trees? People (humans) cut down the trees for their needs.
3. What is the safest place for monkeys? A forest — it provides food, shelter, and protection.
4. What is a habitat? A dwelling place where an organism lives, grows, and reproduces.
Common Mistakes to Avoid
1. Confusing taproot with fibrous root. Taproot has one main root (e.g., mango, neem); fibrous root has many similar-sized roots (e.g., grass, paddy). Remember: Taproot = Dicot, Fibrous = Monocot.
2. Saying "root is modified into spines." It is leaves that are modified into spines in desert plants like cactus. Roots are modified for storage (carrot, beetroot).
3. Confusing terminal bud with axillary bud. Terminal bud is at the tip of the stem (apex); axillary bud is in the axil of a leaf (where leaf meets stem).
4. Writing "stomata function = transpiration only." While stomata do help in transpiration, their primary function as per the textbook is photosynthesis (gas exchange — CO₂ in, O₂ out).
5. Calling ginger a root. Ginger is an underground stem — it has nodes, internodes, and buds, which roots do not have.
6. Confusing terrestrial with aquatic habitat. Mountain = terrestrial (land); pond/lake = freshwater (aquatic). Do not mix these up.
7. Forgetting the full equation of photosynthesis. Always mention all four requirements: Sunlight, Chlorophyll, Carbon dioxide, Water — and both products: Glucose (food) + Oxygen.
Exam Checklist
Before your exam, make sure you can:
- [ ] Define habitat and classify habitats into aquatic (freshwater, marine) and terrestrial (forest, grassland, desert, mountain)
- [ ] Explain photosynthesis with its full equation (inputs and outputs)
- [ ] Distinguish between taproot and fibrous root systems with examples
- [ ] Describe the structure of a leaf (leaf base, petiole, lamina, midrib, veins, stomata)
- [ ] List and explain the functions of root (fixation, absorption, conduction, storage)
- [ ] List and explain the functions of stem (support, conduction, storage)
- [ ] Compare herbs, shrubs, and trees with examples
- [ ] Explain adaptations of desert plants (spines, thick stem, deep roots) and aquatic plants (air chambers, reduced roots, waxy leaves)
- [ ] Identify plant modifications: tendrils (sweet pea, bitter gourd), spines (cactus, opuntia), storage roots (carrot, beetroot), storage stems (ginger, potato, sugarcane)
- [ ] Differentiate between terminal bud and axillary bud
- [ ] Arrange plant parts and functions in correct sequence (e.g., fixation → absorption → conduction → transpiration)
- [ ] Answer HOTS questions on why cactus stem performs photosynthesis and why ginger is a stem