Chapter 3
Food And Health
E. Answer the following questions.
Why is a balanced diet required for good health?
Ans - A balanced diet provides all essential nutrients in the right amount, which helps in body growth, energy, and protection from diseases.
Why is water essential for our body?
Ans - Water is essential because it helps in digestion, regulates body temperature, removes waste through urine and sweat, and transports nutrients.
Why should one take protein in his/her diet daily?
Ans - Proteins help in body growth, repair of tissues, and formation of new cells, which is especially important for growing children.
Name different nutrients present in food. Describe at least one function of each.
Carbohydrates – Give energy
Proteins – Help in growth and repair
Fats – Provide energy and help absorb vitamins
Vitamins – Protect from diseases (e.g., Vitamin C prevents scurvy)
Minerals – Help in body functions like bone strength (e.g., Calcium)
Water – Helps in digestion and maintaining body temperature
Roughage – Aids digestion and prevents constipation
Vitamin D is also called the sunshine vitamin. Give reason.
Ans - Vitamin D is called the sunshine vitamin because our body produces it when the skin is exposed to sunlight.
Science and Sense
Why should we not eat cut fruits and uncovered food?
Ans - We should not eat cut fruits and uncovered food because cut fruits and uncovered food can be contaminated by dust, flies, and germs, which may cause food poisoning or diseases.
Observe and Explore – Home Activity
Day-wise Observation Table:
Days
Change in Colour
Change in Smell
1
No visible change
Normal smell
2
Slight spots appear
Slightly sour smell
3
Green/white patches
Stronger unpleasant smell
4
Patches become larger
Foul smell
5
Mold fully covers it
Very foul smell
6
Bread fully rotten
Extremely bad smell
Chapter 4
Pollination
E. Answer the following questions.
The different parts of a plant are root, stem, leaves, flowers, fruits, and seeds.
2. What is androecium?
Androecium is the male reproductive part of a flower. It includes anther and filament.
3. Name the parts of female reproductive organ of a flower.
Stigma, style, and ovary (together called pistil or gynoecium) are the parts of female reproductive organ of a flower.
4. How do the colours and fragrance of a flower help in reproduction?
The bright colours and sweet fragrance attract insects and other pollinators, which help in transferring pollen from one flower to another, aiding in pollination.
5. Describe the various ways of pollination.
- Self-pollination – Pollen is transferred from anther to stigma of the same flower or same plant.
- Cross-pollination – Pollen is transferred from the anther of one flower to the stigma of a flower on a different plant of the same species.
- Agents like wind, insects, birds, and water help in pollination.
6. What are pollinators? Give any three examples.
Pollinators are agents that help in the transfer of pollen from anther to stigma.
Examples: Bees, butterflies, and wind
Science and Sense
Q no 1. How does wind help in reproduction in plants?
Wind carries the pollen grains from the anther of one flower and helps them land on the stigma of another flower, allowing fertilization and reproduction.
Q no. 2 “Rose is a perfect flower.” What is the meaning of being a perfect flower?
A perfect flower has both male (stamen) and female (pistil) reproductive organs, allowing it to reproduce on its own.
E. Give one word for the following:
Reproduction of new plant by fertilization – Sexual reproduction
Agents that help in pollination – Pollinators
Growing plants from different parts such as root, stem or leaf – Vegetative reproduction
A plant that grows from its leaves – Bryophyllum
The buds of potatoes – Eyes
F. Answer the following questions.
What is reproduction? What are its different types?
Reproduction is the process by which plants produce new individuals.
It is of two types:
Sexual reproduction
Asexual reproduction (e.g., vegetative propagation)
Describe the process of sexual reproduction in plants.
In sexual reproduction, pollen from the anther is transferred to the stigma (pollination). It moves down the style to the ovary, where it fertilizes the ovule. The fertilized ovule becomes a seed and the ovary turns into a fruit.
What are the necessary conditions for seeds to germinate?
Seeds need air, water, warmth, and space to germinate.
What is germination?
Germination is the process by which a seed develops into a new seedling or baby plant under suitable conditions.
Describe any three methods of vegetative reproduction in brief.
By stem (e.g., rose) – New plants grow from stem cuttings.
By leaves (e.g., bryophyllum) – New plantlets grow from leaf edges.
By roots (e.g., carrot) – Roots store food and grow into new plants.
What is seed dispersal? Name the agents of seed dispersal.
Seed dispersal is the process of scattering seeds away from the parent plant.
Agents: Wind, water, animals, explosion
Science and Sense
Why is the dispersal very important?
Dispersal is important because it provides space, air, water, and sunlight for each seedling to grow properly without overcrowding.
Why do plants need to reproduce?
Plants need to reproduce to ensure the continuity of their species.
Learn with Fun
A. Crossword Puzzle
Down:
A plant that reproduces through stem cutting – Rose
The part of female reproductive organ of flower that changes into fruit – Ovary
Scattering of seeds away from mother plant – Dispersal
Male part of a flower – Stamen
Across:
5. A sac-like part of flower that contains pollens – Anther
6. An agent of plant pollination and seed dispersal – Wind (or Insect)
7. The female reproductive part of flower – Pistil
8. The dust-like particles in flowers that transfer through insects, birds, wind etc. – Pollen
E. Answer the following questions.
Define matter.
Matter is anything that occupies space and has mass.
What are soluble substances?
Soluble substances are those that dissolve in a liquid (usually water), like salt or sugar.
Name the main gases present in air.
Nitrogen
Oxygen
Carbon dioxide
Argon
Name three states of matter. Compare the properties of three states of matter.
Property
Solid
Liquid
Gas
Shape
Definite
No definite shape
No definite shape
Volume
Definite
Definite
No definite volume
Particle Arrangement
Closely packed
Less tightly packed
Very loosely packed
Compressibility
Cannot be compressed
Slightly compressible
Easily compressible
Does the volume of a liquid change if a solid gets dissolved in it? If no, why?
No, the volume doesn’t change much because the solid particles settle into the spaces between the liquid particles.
What is a solution?
A solution is a uniform mixture of two or more substances. It is formed when a solute dissolves in a solvent.
What is the composition of air?
Air is composed mainly of:
78% Nitrogen
21% Oxygen
1% other gases (like carbon dioxide, argon, etc.)
How are land breeze and sea breeze caused?
Sea breeze occurs during the day: land heats up faster than water; warm air over land rises and cool air from the sea moves in to take its place.
Land breeze occurs during the night: land cools faster than sea; warm air over the sea rises and cool air from the land moves to the sea.
Science and Sense
Why can’t we press a solid?
Because the particles of a solid are closely packed, leaving no room for compression.
Why can gases be squeezed into a smaller space?
Because the particles in gases are far apart, allowing them to be compressed easily.
Why are the ventilators in houses provided higher up in the walls, whereas windows are made lower down?
Because warm air rises, and ventilators allow the hot air to escape, while cooler air enters from lower windows.
Learn with Fun
A. Unscramble the words:
HILQUD → LIQUID
EINSMTTIDEAON → SEDIMENTATION
ENDACAIOTTN → DECANTATION
TSOM R → STORM
NNTOGEIR → NITROGEN
B. Use the hints to complete the words:
It occurs during day time from sea to land.
S E A B R E E Z E
These are provided above window to act as passage for hot air to move out.
V E N T I L A T O R
It is a technique to separate an insoluble solid from a liquid.
F I L T R A T I O N
A gas present in air that is used to inhale.
O X Y G E N
Chapter 7Interdependence in living beings: Plants and AnimalsE. Answer the following questions.
What is environment?
Environment is everything that surrounds us—living (biotic) and non-living (abiotic) components.
What are producers?
Producers are organisms (like green plants) that can make their own food using sunlight, air, and water through photosynthesis.
What are consumers?
Consumers are organisms that depend on other organisms (usually plants or animals) for their food.
Give examples of biotic and abiotic components.
Biotic: Plants, animals, humans, fungi
Abiotic: Air, water, soil, sunlight
What is a food chain? Give an example of a food chain in a forest.
A food chain shows how energy is passed from one organism to another.
Example: Grass → Deer → Tiger
What is the importance of decomposers in a food chain?
Decomposers break down dead plants and animals into simpler substances, returning nutrients to the soil. This helps in maintaining the balance of nature.
How are living organisms interdependent on each other?
Plants provide food and oxygen.
Animals depend on plants and also help in pollination, seed dispersal.
Humans depend on plants and animals for food.
All living beings need one another directly or indirectly to survive.
What are the various causes of imbalance in nature?
Deforestation
Pollution
Excessive hunting
Burning fossil fuels
Overuse of natural resources
Science and Sense
How are trees helpful in maintaining ecological balance?
Trees provide food and shelter to many animals.
They produce oxygen and absorb carbon dioxide.
They help in rainfall and keep the environment cool and clean.
What happens if all tigers are removed from the earth?
The population of herbivores (like deer) will increase rapidly, leading to overgrazing and destruction of plant life, disturbing the ecological balance.
Learn with Fun – Crossword
Across:
FLORA – Plant species of biosphere
BIOSPHERE – Environment of living organisms
CONSUMERS – Organisms that consume the food made by producers
ENVIRONMENT – The surroundings around us
PRODUCERS – Organisms that make their own food
Down:
ABIOTIC – Component of environment comprising all the non-living things
CARBONDIOXIDE – A greenhouse gas
BIOTIC – Living component of environment
DECOMPOSERS – Organisms that help to enrich soil by recycling nutrients
Chapter 8Sound and NoiseE. Give two examples of each
Soft sound
Chirping of birds
Flowing water
Noise
Honking of vehicles
Loudspeakers
Health problems caused due to noise
Headache
Hearing loss
Sounds of intensity less than 80 dB
Human conversation
Television at low volume
F. Answer the following questions
How are we able to produce sounds?
We produce sound when our vocal cords vibrate as air passes through them during speaking or shouting.
What are pleasant and unpleasant sounds?
Pleasant sounds are those we enjoy (e.g., music, birdsong).
Unpleasant sounds or noise are loud, harsh, and disturbing (e.g., traffic noise).
What are warning sounds?
Warning sounds alert us to danger.
Examples: fire alarms, sirens, ambulance horns.
What are the harmful effects of loud noise?
Headache
Hearing loss
High blood pressure (hypertension)
Irritation and lack of concentration
What are the different ways of reducing noise pollution?
Planting trees
Using soundproofing in buildings
Honking only when necessary
Reducing volume of music systems and TVs
Making laws against use of loudspeakers at odd hours
Science and Sense
“Honking of vehicles is also a warning sound.” Do you agree with this? Give reason.
Yes, I agree. Honking is used to alert people and other vehicles that a car is coming or needs way to move forward.
Reduction in noise pollution is possible through contribution of every individual. Do you agree?
Yes, because each home can produce noise through TV, music systems, etc. Controlling volume at home is our personal responsibility, and everyone’s effort can reduce overall noise.
B. Unscramble the words
IRNSE → SIREN
ECIBDLE → DECIBEL
SWEITHL → WHISTLE
ESOIN → NOISE
PRTYHESE NIO → HYPERTENSION
