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 huge envelope of air surrounded the earth is called Atmosphere.
(i) This envelope is thicker near the earth's surface.
(ii) As we go higher up, the density and the availabillty of air gradually decreases.
(iii) Movement of wind, Presence of water vapours for cloud formation are the vital roles of atmosphere.
(iv) Troposphere is the responsible layer for the weather we experience on earth.
(v) Stratosphere has the Ozone layer which protects all life on earth from the harmful UV rays of the sun.

(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

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.

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) Robert Hook designed the compound microscope.
(ii) He published a book named "Micrographia" in the year 1665.
(iii) He introduce the term cell, which from the latin word "cellula" means a small chamber.
(iv) He observed many objects like Butterfly's wings, Bee's compound eyes under microscope.

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.

Cheese canbe separated from milk by
(i) Filtering the mixture through a fine cloth or strainer.
(ii) The solid particles will be retained by the strainer and unwanted liquid will pass through.

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

We have eukaryotic cells.

If the clothes of a person catch fire,
(i) STOP him where he is
(ii) DROP to the floor if he stands up
(iii) ROLL him on the floor.
Through this activities, we can save the person without big loss.

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.

K₁, K₂  should be closed.

(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.

The green leaves prepare food by the.process of photosynthesis.

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) Common cold
ii) Influenza

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

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

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