Exercise Solutions Available
Step-by-step answers for all textbook questions in this chapter
Plants in Daily Life — Exercise Solutions
Use this page alongside your Samacheer Kalvi textbook. Solve every question on your own first, then check the solutions below.
Note: In the current Samacheer Kalvi syllabus, "Plants in Daily Life" is Unit 5 of Term 3. The content below covers all textbook exercises.
I. Choose the Correct Answer (MCQs)
Hummingbirds have long beaks that reach deep into flowers to drink nectar. While doing so, pollen sticks to their beaks and feathers and gets carried to the next flower, enabling cross-pollination.
Neem leaves and neem oil contain azadirachtin, a natural insect repellent. Neem-coated urea is also used in agriculture to repel pests.
Potato is a stem tuber — it grows underground but is a modified stem, not a root. Carrot, radish, and turnip are true taproots that store food.
Turmeric contains curcumin, which has been scientifically studied for its anticancer, anti-inflammatory, and antioxidant properties.
The Banyan tree (Ficus benghalensis) is India's national tree. Its branches produce aerial roots that grow into new trunks, allowing a single tree to spread over a large area.
II. Fill in the Blanks
1. Every year, October 16 is celebrated as World Food Day.
2. Cotton is an example of textile fibre.
3. "I am the state tree of Tamil Nadu. Who am I?" — Palmyra palm (Panai Maram).
4. The juice of the leaves of the Tulasi plant relieves cough and bronchitis.
5. The edible seeds of leguminous plants are called pulses.
III. True or False (with corrections)
Q1. Plants grown for decorative purposes are called softwood.
Plants grown for decorative purposes are called ornamental plants (e.g., jasmine, rose, crotons). Softwood refers to wood from gymnosperm trees like pine.
Q2. Silkworm eats mulberry leaves.
Silkworms (Bombyx mori) feed exclusively on mulberry leaves. This is the foundation of sericulture (silk farming).
Q3. Cauliflower is used for ornamental purposes.
Cauliflower is a vegetable used as food. The flower of the cauliflower plant is eaten. Ornamental plants include jasmine, rose, and hibiscus.
Q4. Cotton cloth is not suitable for the summer season.
Cotton cloth is suitable for summer. It absorbs sweat and allows air circulation, keeping the body cool. Synthetic fabrics like polyester trap heat and are less comfortable in summer.
Q5. Sugarcane is used as biofuel.
Jatropha is the plant used as biofuel, not sugarcane. Jatropha seeds yield oil that can be processed into biodiesel. Sugarcane is primarily a food crop (source of sugar and jaggery).
IV. Match the Following
| Sl. No. | Column A | Answer | Column B |
|---|---|---|---|
| 1 | Fibre yielding plant | → Hemp | Chloramine |
| 2 | Hardwood | → Teakwood | Spice |
| 3 | Neem | → Chloramine | Hemp |
| 4 | Clove | → Spice | Cereals |
| 5 | Millet | → Cereals | Teakwood |
Explanations:
- Hemp yields strong natural fibre used for ropes and textiles.
- Teakwood is a classic example of hardwood (from angiosperm trees).
- Neem contains chloramine and other compounds with antiseptic and medicinal properties.
- Clove is a spice obtained from dried flower buds of the clove tree.
- Millet is classified under cereals — grains grown for food.
V. Analogy
Q1. mango : fruit :: maize : cereals
Maize is a cereal grain, just as mango is a fruit.
Q2. coconut : fibre :: rose : ornamental (flower)
Coconut yields coir fibre; rose is an ornamental flower plant.
Q3. bees : pollinating insect :: earthworms : tiller of the soil (natural manure)
Bees pollinate flowers; earthworms loosen and enrich soil, earning them the name "nature's plough."
VI. Very Short Answers
Q1. What are food plants?
Plants that serve as the main source of food for humans are called food plants. They include:
| Category | Examples |
|---|---|
| Cereals | Rice, wheat, maize, bajra |
| Pulses | Bengal gram, green mung bean, lentils |
| Vegetables | Beetroot, carrot, potato, spinach |
| Fruits | Mango, banana, apple |
Q2. What are medicinal plants?
Plants that contain ingredients used in drug preparation and traditional medicine to treat diseases are called medicinal plants. They help heal burns, cuts, colds, fevers, and many other ailments.
Examples: Neem, Tulasi, Amla, Aloe vera, Turmeric.
Q3. How does hardwood differ from softwood?
| Feature | Hardwood | Softwood |
|---|---|---|
| Source | Angiosperms (flowering plants) | Gymnosperms (non-flowering plants) |
| Density | Dense and heavy | Lighter and less dense |
| Uses | Furniture, decks, flooring, construction | Plywood, wooden boxes, MDF, paper |
| Examples | Teak, Jackfruit, Rosewood | Pine, Katampu, Cedar |
Q4. What is a spice?
Spices are aromatic parts of tropical plants traditionally used to flavour, colour, or preserve food. They may come from bark (cinnamon), roots (ginger), leaves (curry leaves), flowers (clove), or seeds (cardamom).
Common Indian spices: Black pepper, turmeric, clove, nutmeg, cinnamon, cardamom.
Q5. Name any three medicinal plants available in your area.
1. Neem — leaves used as antiseptic and mosquito repellent 2. Tulasi — leaves relieve cough, cold, and bronchitis 3. Aloe vera — gel used for skin burns and wounds
(Other acceptable answers: Amla, Turmeric, Ashwagandha)
Q6. What are the uses of timber?
Timber is used for:
- Construction of buildings, bridges, and houses
- Furniture — tables, chairs, beds, doors, and windows
- Valued for durability, stylish finish, and resistance to temperature changes
VII. Short Answers
Q1. What is a symbiotic relationship?
A symbiotic relationship is a close, long-term interaction between two different species that benefits at least one of them. In the context of plants and animals:
- Bees get nectar from flowers while pollinating them — both benefit (mutualism).
- Birds and animals eat fruits and disperse seeds, helping plants reproduce.
- Silkworms feed on mulberry leaves, enabling silk production that benefits humans.
Q2. Write the uses of neem.
| Part | Uses |
|---|---|
| Neem leaves | Mosquito repellent, antiseptic, treatment for skin disorders, intestinal worms, eye problems |
| Neem flowers | Used to treat intestinal worms and digestive issues |
| Neem oil | Rich in Vitamin E and fatty acids; used in skin care, medicine, and as bio-pesticide |
| Neem wood | Making furniture and agricultural tools |
| Neem-coated urea | Slow-release fertilizer that reduces nitrogen loss and repels pests |
Q3. Name any five plants and their parts that we eat.
| Plant | Part Eaten | Category |
|---|---|---|
| Carrot / Radish / Turnip | Root | Root vegetable |
| Potato / Ginger / Onion | Stem | Stem vegetable |
| Spinach / Cabbage / Coriander | Leaf | Leafy vegetable |
| Cauliflower / Banana flower | Flower | Flower vegetable |
| Wheat / Rice / Beans | Seed | Cereal / Pulse |
| Mango / Apple / Coconut | Fruit | Fruit |
VIII. Detailed Answers
Q1. Write short notes on Timber Yielding Plants
Wood needed for construction and furniture is obtained from timber-yielding plants. Timber is valued for its durability, stylish finish, and resistance to temperature changes.
Commercial timbers are classified into two categories:
Q2. Comment on the importance of Plant-Animal Interaction
Plant-animal interaction is a vital ecological relationship that sustains both the environment and the economy:
IX. Higher Order Thinking Skills (HOTS)
Q1. Deserts do not have water. Why?
Deserts receive extremely low rainfall (less than 25 cm per year) because:
- There are no lakes, seas, or rivers nearby to provide moisture for evaporation and cloud formation.
- Without clouds, there is no precipitation.
- The hot sun heats the earth's surface directly, causing high evaporation of whatever little moisture exists.
- The dry soil cannot retain water, so even occasional rain quickly drains away or evaporates.
- As a result, deserts remain arid with virtually no surface water or groundwater reserves.
Q2. Kavitha said, "Palm tree is a tall tree, so it gives hardwood." Do you agree?
No, I disagree. A palm tree is tall but does not give hardwood:
- Palm trees belong to the family Arecaceae and have a cellular structure that is completely different from both hardwood and softwood trees.
- The trunk of a palm tree is hollow and soft inside — it consists of fibrous material, not true wood.
- Unlike hardwood trees (which have annual growth rings and dense xylem), palm trunks lack secondary growth.
- Therefore, palm wood cannot be used for durable furniture or construction.
- Palm trees are valued instead for their products: coconut, palm jaggery, palmyra fruit, and palm leaf fibre.
Q3a. Soil fertility is increased by bacteria. How?
- Certain bacteria like Rhizobium and blue-green algae (cyanobacteria) perform nitrogen fixation.
- These bacteria absorb atmospheric nitrogen (N₂) and convert it into compounds like ammonia and nitrates that plants can absorb through their roots.
- Rhizobium lives in the root nodules of leguminous plants (pulses), forming a symbiotic relationship — the plant provides food, and the bacteria provide usable nitrogen.
- Blue-green algae in paddy fields also fix nitrogen, increasing soil fertility naturally.
- This reduces the need for chemical fertilizers and maintains long-term soil health.
Q3b. Honey bees are essential for the reproduction of plants. Why?
- Honeybees visit flowers to collect nectar (for making honey).
- While collecting nectar, pollen grains stick to their hairy body and legs.
- When the bee visits the next flower, some of these pollen grains fall on the stigma of that flower.
- This process, called cross-pollination, is essential for the formation of seeds and fruits in many plant species.
- Without bee pollination, many crops (apples, almonds, mangoes, etc.) would have significantly reduced yields.
- Bees are considered the most important pollinators in agriculture, making them vital for both plant reproduction and food security.
Common Mistakes
1. Confusing potato with a root — Potato is a modified stem (stem tuber), not a root. Carrot, radish, and turnip are true roots.
2. Calling ornamental plants "softwood" — Ornamental plants are grown for decoration (jasmine, rose). Softwood refers to wood from gymnosperm trees (pine, cedar).
3. Saying sugarcane is a biofuel plant — The correct biofuel plant is Jatropha. Sugarcane is a food crop (source of sugar and jaggery).
4. Thinking palm trees yield hardwood — Palm trees have hollow, fibrous trunks and are neither hardwood nor softwood. They belong to a completely different structural category.
5. Confusing hardwood vs. softwood source — Hardwood comes from angiosperms (flowering plants like teak); softwood comes from gymnosperms (non-flowering plants like pine).
6. Writing only "food" as a use of plants — Plants provide food, medicine, fibre, timber, spices, rubber, oils, oxygen, and ornamental value. Always give a broad answer.
7. Listing only one benefit of neem — Neem has multiple uses: leaves (mosquito repellent, antiseptic), flowers (intestinal worms), oil (skin care, bio-pesticide), wood (furniture), and neem-coated urea (agriculture).
Exam Checklist
Before your exam, make sure you can answer:
- [ ] Name 5 categories of economic plants and give 2 examples of each
- [ ] Distinguish between hardwood and softwood with examples
- [ ] Explain the symbiotic relationship between plants and animals (at least 3 examples)
- [ ] List 5 plants and the edible parts we consume
- [ ] Write 4 uses of neem with specific plant parts
- [ ] Explain why bees are essential pollinators
- [ ] Define: food plants, medicinal plants, pulses, timber, ornamental plants, spices
- [ ] Correct the statement: "Palm tree gives hardwood" — explain why it is wrong
- [ ] Name the state tree of Tamil Nadu (Palmyra palm) and the national tree of India (Banyan)
- [ ] Explain nitrogen fixation by bacteria and its role in soil fertility