PHOTOSYNTHESIS:
Plants manufacture food by a process called photosynthesis. During photosynthesis, carbon-dioxide from the air and water from the soil react in the presence of sunlight and chlorophyll to produce food.
\(\text { Carbon-di-oxide }+\text { water } \underset{\text { Chlorophyll }}{\stackrel{\text { Sunlight }}{\longrightarrow}} \text { food }+\text { oxygen }\) 
RESPIRATIO IN ANIMAL :
When we breathe in air, the oxygen present in the air reacts chemically with digested food within the body to produce carbon-di-oxide gas, water vapour and energy.
Food + Oxygen  Carbon-di-oxide + Water + Energy
(i) carbon-di-oxide formed during respiration dissolves in the blood and is exhaled out of the body through the lungs.
(ii) Plants release oxygen during photosynthesis which is much more than the oxygen consumed by the plants, during respiration.
(iii) Thus, the balance of O₂ & CO₂ in air is maintained.

Conductors:
(i) The rate of flow of electric charges in a circuit is called electric current.
(ii) The materials which allow electric charges to pass through them are called conductors.
(iii) Examples: Copper, iron, aluminium, impure water, eafth etc.
Insulators (Non -Conductors) : 
(i) The material which do not allow electric charges to pass through them are called insulators or non- conductors.
(ii) Examples: plastic, glass, wood, rubber, chinna clav, ebonite etc.

(i) Computers are used in various fields.
(ii) In textile shop it is used for billing.
(iii) Computers are used to control large and small machines.
(iv) Computers are most important educational tools for teachers and learners.
(v) In Railways it is useful to book tickets and for other purposes.
(vi) It is also used in banks, ATM's, Post offices and in many places.
(vii) We can save many data and convert it into information.

FUNCTIONS OF THE ROOT:
i) The root fixes the plant to the soil.
ii) Absorbs water and minerals from the soil.
iii) Stores food in some plants like Carrot and beetroot
FUNCTIONS OF THE STEM:
i) The stem supports the branches, leaves, flowers and fruits.
ii) Transports Water and minerals from roots to upper aerial plant parts.
iii) Transports the prepared food from leaves to other parts through stem.
iv) Stores food as in the case of sugarcane

Linear motion - A coconut falling from a tree
Curvilinear motion - A car driving around a curve
Self rotatory motion - Motion of the wheel in a cart
Circular motion - Athlete running around a track
Oscillatory motion - Swinging of a pendulum
Irregular motion - Movement of people in a bazaar

When there is a change of position of an object with respect to time then it is called motion.
Types of motion:
a) Based on path:
i) Linear motion - a person walking on a straight path
ii) Curvilinear motion - throwing ball
iii) Circular motion - swirling stone tied to the rope
iv) Rotatory motion - a rotating top
v) Oscillatory motion - pendulum of clock
vi) Zig zag (or) Irregular motion - the motion of a bee
b) Based on duration:
i) period motion - movement of hour hand of a clock
ii) Non-periodic  - motion flapping of a flag in wind
c) Based on speed:
9) Uniform motion -  motion of a train at a constant speed
ii) Non-uniform motion - a vehicle moves in different speed

Measuring the volume of irregular solid by displacement method.

(i) Take a graduated measuring cylinder and a stone.
(ii) Fill with water to certain level and mark it.
(iii) Tie the stone with a piece of fine thread.
(iv) Immerse the stone completely in to the water.
(v) We can observe the water level and mark it.
(vi) The water level is increased.
(vii) Find the increased level of water.
(vii) It would be equal to the space taken by stone.
(viii) This will be the volume of irregular stone.

Distance travelled (d) = 400 km
Time taken (t) = 5 hour
Average Speed (s) = \(\frac{d}{t}=\frac{400}{5}=80\) 
Average Speed = 80 kmph (or) Km/hr.

If the diaphragm is not moved, breathing will not occur. It leads to death.

a) melting of wax and
d) Solidification of the molten wax can be reversed.
Burning of candle is a physical / reversible change. That is,
\(\text { Solid wax } \underset{\text { Cooling }}{\stackrel{\text { Heating }}{\rightleftarrows}} \text { molten wax }\)

The heat is escaping from the room because the room temperature is higherthan atmosphere. Heat energy flows from higher temperature to lower temperature.

(i) Using beakers, the mustard oil is separated by the process of decantation, because oil being lighter than water, floats on water.
(ii) Next filtration is using a funnel and filter paper and thus water gets separated from chalk powder and coins.
(iii) By hand-picking method, the coins are separated frorn chalk powder.

(i) The rib cage is made up of 12 pairs of curved, flat rib bones.
(ii) It protects the delicate vital organs such as heart and lungs.

They are exposed to harsh weather conditions, dust, pollution, heat and cold. So, they can have an adverse effect on their health. Hence, they weak a mask on duty.

No. Deforestation can be an undesirable change. That is, Deforestation is harmful to our environment and not desired by us.

No the cell used in the clock cannot give us an electric shock because the voltage is very low in the cell.

(i) Yes, a rubber ball can be called a solid because it doesn't flow away like liquids or gases.
(ii) But the rigidity of the rubber ball is less than the external force. So it changes its shape.

Eyes, Ears, Nose, Tongue and Skin are the sense organs.

Trachea commonly called wind pipe - allowing the passage of air to lungs.

Cytoplasm is called as "Area of movement"

Cell wall and chloroplast found only in plant cell

(i) Cell membrane
(ii) Cytoplasm
(iii) Nuclecus are the essential components of a cell.

If we remove the fish from the aquarium and keep it in a dark place with green plants,
(i) they can't have sunlight and
(ii) have no CO₂ from the water produced by fish as they breathe.
(iii) Simply say, there is no possibility for photosynthesis to make their food.

If we remove plants from the aquarium
(i) All types of wastes created by aquatic animals, excess food and decaying materials level will increase in water.
(ii) The dissolved oxygen level in water will decrease.
(iii) Algae will grow due to excess nutrients and light in aquariums.
(iv) Some types of fish even breed and lay eggs on the leaves of ths plants. This will affect.

When solute is dissolved in a solvent it forms a solution.
Solute + Solvent ⟶ Solution

Changes which take place over a long period of time are known as Slow changes.

Plants decaying is a chemical change.

The Iron chain is the conductor from the above figures.

(i) The Water heater
(ii) Iron box
(iii) Electric kettle etc.

The locomotory organ of Amoeba is pseudopodia.

Lemon juice is a mixture because it is a miture of lemon extract, water and sugar.  This is a mixture though the amount of sugar and water added is different we know that, in a mixture the components are mixed in any proportion.

Matter is defined as anything that has mass and takes up space.

Cactus, Agave, Aloe, Bryophyllum

Based on habitat, plant are classified as
i) aquatic plants
ii) terrestrial plants.

(i) Data is the information that has to be processed.
(ii) They are in the form of numbers, alphabets and images.

A computer is an electronic device that process the data and information according to our needs.

(i) Micro organisms are wide spread in nature.
(ii) They are the smallest organisms on Earth.
(iii) Most of them cause diseases.

(a) Food items rich in fat - Ex: Butter, Ghee.
(b) vitamin deficiency diseases - Ex: Night blindness, Beri-beri

c. Flash card

1 millimetre < 1 centimetre < 1 Metre < 1 kilometre.

Both A and R are correct and R is the correct explanation for A.