Endocrine system:
(i) Endocrine glands are present in the body produce chemical substances called hormonds.
(ii) It regulates various fundions of the body and maintains the internal environment.
Nervous system:
(i) Nervous system is well developed by neurons or nerve cells.
(ii) Nervous system along with the endocrine system doing conduction and co-ordination in human body.

(a) Slow and fast change
(i) Slowchange - Changeofseasons
(ii) Fast change - Bursting of fire crackers
(b) Reversible and irreversible change
(i) Reversible change - Stretching of rubber
(ii) Irreversible change - Digestion of food
(c) Physical and chemical change
(i) Physical change - Melting of Ice
(ii) Chemical change - Rusting of Iron
(d) Natural and man-made change
(i) Natural change - Rotation of the earth
(ii) Man-made change - Cooking
(e) Desirable and undesirable change
(i) Desirable change - Milk changing to curd
(ii) Undesirable change - Deforestation

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

Method 1:
(i) Place a string along the curved line, Make sure that the stringcovers every bit of the curved line.
(ii) Mark the points where the curved line begins and ends on the string.
(iii) Now, stretch the string along the length of a meter scale and measure the distance between the two markings of the string.
(iv) This will give us the length of a curved line.
Method 2:
(i) Draw a curved line AB on a piece of paper.
(ii) Separate the legs of the divider by 0.5 cm or 1 cm using a ruler.
(iii) Place it on the curved line starting from one end. Mark the position of the other end. Move it along the line again and again cutting the line into number of segments of equal lengths. The remaining parts of the line can be measured using a scale.
(iv) Count the number of segments.
(v) Therefore, the length of the line = (number of segments x length of each segment) + length of the left over part.

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.

Fire extinguishers throw a stream of carbon-, di-oxide while putting - off fire. Carbon-di-oxide covers the fire and cut-off the supply of fresh air to the burning things and stop burning.

We feel hot because the heat is transferred from atmosphere to your body. 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.

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.

Silver is not used to make electric wires because it is expensive.

i) Birds have streamlined body covered with feathers. This body shape provides minimum resistance to air.
ii) They have a pair of wings to fly in the air.
iii) They have hollow and light bones.

(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.

a) Neem tree
b) Mango tree
c) Croutons
d) Coconut tree

Switch, Bulb and Battery are the parts of the electric circuit. Generator is the source of electricity.

Digestion and absorption of food done by digestive system.

Arteries, Veins and capillaries are the blood vessels.

Plant cell,Animal cell and most of fungi.

Cell wall and chloroplast found only in plant cell

Robert hook discovered the cell in 1665.

If you breathe through mouth,
(i) getting oxygen to our muscles faster
(ii) it will cause crooked teeth for children
(iii) it leads to gum disease in adults
(iv) it may cause stress to the heart and lungs.

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.

On strong heating, cane sugar chars to almost pure carbon giving the smell of 'Burnt sugar'.
(i) Initial change - Physical change - melting
(ii) Final change - Chemical change - charring

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

Plants decaying is a chemical change.

yes, I can produce electricity from lemon. Because lemon juice (Acetic acid) acts like a electrolyte.

(i) The measurement of warmness or coldness of a substance is known as its Temperature.
(ii) SI unit of temperature is kelvin

The tail of the bird helps to change the direction of the movements.

Husk or fine dust particles cdnbe separated from rice by the method 'winnowing"

The area where a particular organism actually lives is called its habitat.

Cactus, Agave, Aloe, Bryophyllum

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

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

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