It may lead to flood.

(i) Attractive property: A magnet has the property to attract some substance like iron, cobalt and nickel when brought near it. This property of magnet is called the attractive property.
(ii) Directive property: If we suspend a magnet freely with a thread, then it always aligns itself in the geographic north-south direction when it comes to rest. This is called the directive property of a magnet.

Coal is a combustible solid, petrol is a combustible liquid and CNG is a combustible gas

Periodic change : A change that repeats after a definite time interval is known as periodic change, e.g., phases of moon, heart-beat, etc.
Non-periodic change : A change that does not repeat again and again after a regular interval of time is known as non-periodic change, e.g., earthquake, flood and so on.

No, light cannot pass through opaque objects

The following adaptations are seen in the body of birds.
(i) Bones are hollow.
(ii) Forelimbs are modified into wings.
(iii) Body is streamlined.

Redworms have gizzard (a kind of teeth) in their alimentary canal which can grind the hard particles of garbage. 

Camels have long legs, a hump and padded feet. All of these are adaptive features which help camel to survive in desert habitat.

There are two terminals of an electric cell, i.e. positive and negative terminals.

Air plays an important role in number of musical instruments such as flute, trumpet harmonium.

Rotational and rectilinear motion are performed during the rolling of a ball.

In ancient Egypt, cotton as well as flax were cultivated near the river Nile and were used for making fabrics.

Bean stalk, gourd plants money and grapevines plants all have weak stem but readily climbs up a neighbouring support or a tree. These plants are called climbers.

The materials that can be used are a wire-mesh, a piece of cotton, a piece of fine cloth and strainer.

Vitamin-K and calcium both help in clotting of blood.

Roots, fruits and leaves are edible parts in different plants.

Earthworm has a large number of tiny bristle projections. These bristles are connected with muscles, which help the earthworm in fixing parts of its body to the ground.

Our body needs different kinds of food for some special purposes.
For example,

(i) The stem of Cactus helps to retain water.
(ii) Its leaves are modified into spines to reduce transpiration.
These adaptations help Cactus to survive in a desert.

Following steps are used to separate a mixture of
saw dust and sugar :
(i) Add water to the mixture 
(ii) Sugar present in the mixture dissolves in water but saw dust does not.
(iii) The solution is then filtered through filter paper.
(iv) We will get sugar solution as filtrate and saw dust will remain on the filter paper.
(v) Then the solution is heated and when water evaporates completely, sugar is left behind

As, we know that like poles of a magnet repel each other and unlike poles attract each other.
Thus, the complete table is shown as below:

(a) Pieces of papers can be obtained from newspapers, notebooks, magazines, etc. All of these can be recycled whereas shiny plastic coated papers cannot be recycled. Because plastic is non-biodegradable. The paper which cannot be recycled can be reused to make paper bags, envelopes, etc.
(b) Yes, there is a difference as surface of recycled paper is rough, while that of new sheet of paper is smooth. Recycled sheets are prepared from used papers. This type of paper can be used for making carry bags and other packaging materials.

No, the bulb will not glow in the circuit because the filament of the bulb B is broken and current will not flow in the whole circuit, i.e. the circuit is broken or incomplete.

Take some water in a glass vessel or beaker. Heat it slowly on a tripod stand well before the water begins to boil. Look carefully at the inner surface of the vessel, you will see tiny bubbles inside. These bubbles come from the air dissolved in water.

The shape of the flower on the screen will be same as that of the flower but the shadow of flower is of black colour.

As the temperature outside the refrigerator is higher than the refrigerator. So, when the cooled bottle of water is kept on a table, water vapours gets condensed and as a result, puddle of water appears around the bottle.

Two examples of periodic motions are
(i) Motion of the earth around the sun
(ii) To and fro movement of bob of a pendulum

Objects that float in water are plastic, sawdust, dry leaves, ice, kerosene objects the objects that sink in water are copper, silver, gold, stone, chalk.

To fix the handle, the ring is heated and it becomes slightly large in size. Then, the handle easily fits into the ring. When the ring cools down contracts and fits tightly onto the handle.

Nylon, wool, cotton, silk, polyester, jute
Natural fibres  Wool, cotton, silk, jute.
Synthetic fibres  Nylon, polyester.

If a plant has fibrous root, its leaves have parallel venation.

South India being close to sea, provides plenty of sea animal products like fish, etc. Chiefly grown cereal there is rice.
So, the people there mainly eat rice, fish, meat, etc. Vegetarians make idli, sambhar, uttapam, banana chips, coconut chutney. They use coconut oil as a cooking medium.

It can be found in following ways:
(i) Take the bar magnet with known poles in you hand.
(ii) Take one of the other two iron bars in other hand.
(iii) Bring one side of iron bar towards the south pole of the bar magnet and note down whether it is attracted or repelled.
(iv) Bring other side of iron bar towards the south pole of the bar magnet and again note down the same thing.
(v) If there is an attraction in both cases i.e.,(iii) and (iv), then it is definitely a simple iron bar.
(vi) If there is an attraction in one case and repulsion in other case, then it is a bar magnet.
(vii) Do the same for the third iron bar. Now, poles can be found in following ways-If in case (iii), the bar is attracted, then it is North pole of the identified bar magnet. If the bar is repelled, then it is a south pole of the identified bar magnet.

There are following properties by which we can prove that these materials are different:

The quality of cotton fabrics can be improved by :
(i) improving the quality of soil.
(ii) protecting the crops from pests.
(iii) discarding infected fibres.
(iv) twisting the fibres to make yarn properly.
(v) ensuring minimum or no gaps during weaving.

Cockroaches walk and climb as well as fly in the air. They have three pairs of legs which help them in walking. The body is covered with a hard outer skeleton. This outer skeleton is made of different units joined together which permit movement. There are two pairs of wings attached to the thorax. The cockroaches have distinct muscles-those near the legs move the legs for walking. The thoracic muscles move the wings when the cockroach flies.

Solar Eclipse: When the sun, the earth and the moon come in a straight line with the moon in between the earth and the sun, then the shadow of the moon falls on the earth. This results in solar eclipse. Solar eclipse occurs on a new moon day.

Lunar Eclipse: When the sun, the earth and the moon come in a straight line with the earth in between the moon and the sun, then the shadow of the earth falls on the moon. This results in Lunar eclipse. Lunar eclipse takes place on a full moon day. The shadow consists of two parts. One part is completely dark part of the shadow, where light does not reach from the source of light and this part is known as umbra. Other part is not completely dark, where some light reaches from the source of light and this part is known as penumbra. Penumbra surrounds the umbra.

By following these simple steps, we can make hard gifting boxes or other articles from the recycled paper pulp:
Step I Create a stencil by unfolding a small, one piece cardboard box and trace it on a piece of cardboard that is the same size as your mold. Then, cut out that shape with scissors.
Step II Place the box stencil between your mold and deckle.
Step III Raise the mold, deckle and stencil to the surface in one continuous motion and then remove them from the pulp.
Step IV Remove the box from the stencil and let the paper dry.
Step V Assemble the box by folding and gluing or taping the edges. Decorate it as your need.

This can be done by arranging the circuit as the given diagram.
One terminal should be connected to the terminal of the cell directly and other terminal can be connected using the given wire.

(a) There will be no life on the earth. Oxygen is vital for life. It helps in burning, respiration, photosynthesis, etc. Oxygen is basic need of all living beings.
(b) Nitrogen does not support burning. If nitrogen gas disappear from the atmosphere, things will burn very fast.
(c) Carbon dioxide is needed for photosynthesis which occurs in green plants. In its absence, plants will not be able to prepare their food and hence, there will be no life on the earth.

(a) Plants growing in different places appear different due to the presence of unique adaptive features which can be morphological or functional
(b) It is called a habitat. It provides food, water and shelter, etc., to all living organisms
(c) Two types of habitats have been observed
(i) terrestrial (ii) aquatic
(d) Leaves of cactus present in desert are thorn like (spines) on reduced to green fleshy stem, to reduce rate of transpiration while leaves of trees like deodars have cone or pine-shaped leaves to let show falling on them slide off easily.
(e) Ravi and Ritu both are adventurous, curious and observant. They are learners and have scientific temperament.

Sea water reaches a lake or pond is represented by a diagram:

(a) Rectilinear motion The handle of bicycle will always move in rectilinear path because it cannot do circular or rotatory motion.
(b) Circular motion The Paddles of bicycle will always move circularly around its chain fixing system because it cannot move in forward direction without the whole chain system.
(c) Both rectilinear and circular The wheels of bicycle will move in rectilinear as well as in circular motion because the wheel as a whole will move forward and its point or particles around the rim will execute circular motion.

Physical changes A candle is made up of wax. We take a small candle and measure its length with scale. Now fix this candle on a tile kept on table and light it with burning matchstick. Allow the candle to burn for some time. Now we absorb melting wax comes to side of candle or table. This wax is reversible and we can used this wax.
Chemical changes The wax near the flame burns and gives new substance like carbon dioxide, carbon soot, water vapours, heat and light.

(a) In the given figure:
(i) Petiole (ii) Midrib (iii) Lamina (iv) Vein
(b) The leaf has reticulate venation, the veins in leaf occur in an irregular way forming a net-like structure.
(c) Grass leaves have parallel type of venation. The vein run parallel to each other on both sides of midrib.

(i) happy
(ii) sun
(iii) threshed
(iv) winnowed
(v) handpicked
(vi) sieved
They got a good price as they used appropriate methods of separation to get good quality of flour (atta).

(a) The main sources of calcium minerals are milk, cheese, eggs and green vegetables. It also found in flour and bread.
It helps in formation of bone, teeth and blood clotting.
(b) Magnesium is found in cheese, green vegetable, bread and fish.
It helps in energy transfer and muscles activity. It works with calcium and vitamin-C.
(c) Potassium is found in meat, fruit, eggs, milk, etc.
The main function of potassium is balance in tissue fluid and blood. It also helps in nerve impulse conduction.
(d) Zinc is mainly found in onions, liver and green vegetables.
It works as a enzyme activator in our body.
(e) Iron is found in green vegetables, fresh fruits, etc.
Iron is needed to make haemoglobin present in red blood cells which carry oxygen from the lungs to the body parts.

(a) Food habits of people in Chennai were different as they used coconut oil for cooking and coconut is extensively used in preparing other dishes. Rice was part of every meal, they consume less or no chapatis.
(b) Food habits refer to particular interest towards certain types of food. It is commonly influenced by location, climate and availability.
(c) Sambhar dal is very common. Its main ingredients are dal, condiments, vegetables and oil. All of these ingredients are plant products.
(d) Rajni is friendly, observant and knowledge seeking girl. She is aware of her surroundings which is very important.