Concave mirror can form real image and virtual image of larger size than the object

The process of fusion of the male and the female gametes is called fertilisation.

When the switch is in off position then the circuit from the positive terminal of battery to the negative terminal is not complete. The circuit is then said to be opened and current does not flow throughout the circuit and bulb does not glow.

Yes, because after physical activity we require energy.

We see that the car covers a distance of 5 km in first 10 min. It again covers a distance of 5 km in next 10 min. In the next 10 min, it covers 10 km, then again 10 km in 10 min. Then it covers 5 km in 10 min. This shows that the car travels unequal distances in various slots of 10 min. So we conclude that the car is moving with a non-uniform speed. 

A convex lens bends inwards the light falling on it. It is called a converging lens. On the other hand, concave lens bends outwards the light and is called diverging lens.

Tongue is a fleshy muscular organ attached at the back to the floor or the buccal cavity and free at the front. It can move in all the directions. It mixes the saliva with the food during chewing. It helps in swallowing the food. It has various taste buds which help to detect different tastes of food.

Doors and window frames, table, chair, bed, paper, match stick, gum, spices etc.

Following steps are involved in making wool.
(i) Shearing: First of all, the fleece of the sheep along with a thin layer of the skin is removed.
(ii) Scouring: Sheared skin is thoroughly washed in tanks to remove grease, dust and dirt.
(iii) Sorting: This involves the separation of hairs of different textures.
(iv) Drawing out the fibre: The small fluffy fibres popularly known as 'burrs' are picked out from the hair first, then scoured, dried and finally drawn into fibres.
(v) Dyeing: Finally the fibres can be dyed into a variety of colours.

This means if you have water, you can think of future, i.e. no life is possible without water.

As we know that jute sacks is thermal insulators, it helps ice not to be melt immediately. So, shopkeepers used to cover ice blocks with jute sacks.

The four main parts of a flower are
(i) Sepals
(ii) Petals
(iii) Stamen
(iv) Pistil.

2005 -2015 is the period proclaimed as the International Decade for action on Water for Life.

Hugo, Katrina, Rita, Hud-Hud and Phailin are the various types of cyclones that occurred in the past.

Souring of milk is a chemical change because original substances present in milk lose their nature and identity and form new chemical substances.

The heart is located in the chest cavity with its lower tip slightly tilted towards the left.

Clayey soil absorbs more water but allows less water to percolate

Plants such as gram, pulses and beans are leguminous.

Lime water (calcium hydroxide) is a basic solution.

When the temperature due to the sun's heat reaches to its maximum level it is called maximum temperature and when it goes down to the lowest level it is called minimum temperature.

Fuse is a safety device which prevents our houses, appliances and electric circuit from electrical hazards at the time of the short circuiting or overloading. The fuse works on the basis of heating effects of the electric current. If, by an accident the current exceeds a certain limit this device becomes overheated and melts which breaks the circuit and supply of electricity is stopped. In this way, it helps in prevention of short circuits

The uppermost layer of the forest canopy intercepts the flow of rain drops and most of the water comes down through the branches and stems of the trees. From leaves it drips slowly over branches of the shrubs and herbs. All this slows down the speed of raindrops and also slows down the speed of running water.
Thus, forests act as a natural absorber of rainwater and allows it to seep. It helps to maintain the water table throughout the year. In this way, forests help in controlling floods and maintain steady supply of water.

(i) The problem is of tooth decay which causes toothache.
(ii) One should clean the teeth with a toothbrush twice a day. Chocolates should be avoided.
(iii) She is aware and concerned about the problems arising in the teeth especially of younger children.

The mean temperature for a given month is found in two steps:
(i) First we find the average of the temperatures recorded during the month.
(ii) Second we calculate the average of such average temperature over many years. That gives the mean temperature.

Add a drop of phenolphthalein separately in liquids A, B and C. The one which turns pink is sodium hydroxide, let it be A. Divide this into two parts. Now add a few drops of other solutions in the above solution taken into parts. The solution which again turns solution A colourless is hydrochloric acid. Let it be B. Then solution left is sugar.

Sericulture and moriculture.

The number of problems that can be faced due to shortage of water are as follows
(i) Less amount of pure drinking water will be available.
(ii) Lack of equal distribution of water.
(iii) Drought.

As a fact that warm air is much lighter than the cold air, so being heavier the cold air from air conditioner moves downwards while the hot air moves upwards at the lower level and gets cooled and come downwards once again. So, due to this convection of heat are set in the air and room gets warmer faster.

First sedimentation tank.

These mirrors can be differentiated by bringing our face close to each mirror turn by turn. Since, a plane mirror will produce an image of the same size as our face while a concave mirror will produce a magnified image and our face will look much bigger and on other sides, a convex mirror will produce a diminished image and our face will look much smaller like a small child.

Initial speed = 36km/h\(=\frac{5}{18}\times36=10m/s\)
Final speed = 54km /h\(=\frac{5}{18}\times54=15m/s\)
Increase in speed = Final speed - Initial speed = (15-1 0) m/s = 5 m/s
(b) Priyanka applied the brakes at a right time while driving the car and prevented her family and the person on rickshaw from meeting with an accident.

Differences between aerobic and anaerobic respiration are as follows

Similarities between aerobic and anaerobic respiration are as follows
(i) Both break down the glucose.
(ii) Release of energy takes place in both.
(iii) CO2 is the common product in both.

The following three precautions must be taken to protect oneself from the lightning of thunderstorm
(i) Do not take shelter under an isolated tree.
(ii) Do not lie on the ground
(iii) Do not take shelter under an umbrella with a metallic end.

Plants absorb a large quantity of water from the soil because they need nutrients which are dissolved in the water. The excess water evaporates through the stomata present on the leaf surface by the process of transpiration.

We know that for rusting, the presence of both oxygen and water (water vapours) is essential.
Thus, in coastal areas, the air contains high moisture which means more humid environment and rusting becomes faster.
Whereas in deserts, moisture in air is less, hence rusting of iron is very slow there.

Plants utilise carbon dioxide from air and water and minerals are derived from soil (through roots) as raw material for photosynthesis. Besides these chlorophyll present in green leaf is necessary for the process and sunlight is the source of energy which is converted into chemical energy during the process of photosynthesis.

There are three different types of soil
(i) Sandy soil containing sand particles in them.
(ii) Clayey soil contains clay particles with small amount of humus in it. It is a fertile soil.
(iii) Loamy soil is a mixture of sand, clay silt and humus. It is a fertile soil

Difference between respiration and combustion

(i) Actually, millions of people in our country do not get enough water. Especially during summer, in many areas there is an acute shortage of water, taps running dry, long queues for water and even fight for demand of water in a common sight.
(ii) Causes: Due to less amount of rainfall in some areas, not only water bodies like ponds, rivers become dry also due to excess extraction of ground water, water table goes down.
Remedies: Public and government both should be concern and show awareness towards this crisis. By drip irrigation system and water harvesting technique, we cannot only save water from wastage but also recharge ground water.
(iii) In these areas of hot dry and arid climate the studies of children are badly affected.

Take a boiling tube. Stretch a balloon tightly over the neck of the tube. Pour some hot water in a beaker. Insert the boiling tube with the balloon in the hot water. Observe for any change in shape of balloon. We see that balloon lifts upward. Take the tube out, let it cool down to the room temperature. Take some ice cold water in another beaker and place the boiling tube in it. The balloon inflates when the boiling tube is placed in hot water. But the same balloon deflates when tube is kept in cold water. This activity shows that warm air rises up and warm air is lighter than the cold air. In this way, we can say that difference in temperature also involved in making speed of wind.

Blood is a liquid which is composed of following two parts:
(i) Plasma: The fluid part of the blood is called plasma.
(ii) Cells: There are three kinds of cells suspended in the plasma of blood
(a) Red Blood cells (RBC): These cells contain a red pigment called haemoglobin. Haemoglobin binds with oxygen and transports it to all the parts of the body and ultimately to all cells. It will be difficult to provide oxygen efficiently to all the cells of the body without haemoglobin. Due to the presence of haemoglobin the blood appears red.

(b) Platelets: The third type of cells found in the blood are platelets. Their function is to form clot to prevent loss of blood when we are injured. 
(c) White Blood Cells (WBC): WBCs fight against germs that may enter our body and thus protect us from infection.

(i) Train-II might have gone in higher speed then the train-I as it takes less time to cover the same distance.
(ii) For train - I
Distance = 320 km
Time taken = 4 h 30 mins
= \(4\frac { 1 }{ 2 } \)
Speed = \(\frac { distance }{ Time } \)
\(\frac { 320 }{ 9/2 } km/h\)
= \(\frac { 320\times 2 }{ 9 } =\frac { 640 }{ 9 } \)
= 71.1 km.h
For train - II
Distance = 320km
Time taken = 30 mins less than the first train
=4h
Speed = \(\frac { Distance }{ Time } \)
= \(\frac { 320 }{ 4 } km/h\)
=80 km/h
(iii) The graph in figure (a) is of train-I
The graph in figure (b) is of train-II.

All changes in the weather are caused by the sun. The energy sent out by the sun is so huge that it is the source of all heat and light on the earth. Energy absorbed and reflected by the earth surface, oceans and the atmosphere play an important role in determining weather of any particular place.

Use both red and blue litmus solution and predict the colours in each case. In acidic medium, blue litmus solution turns to red. In basic medium, red litmus solution turns to blue

(a) The electric iron works on the basis of heating effect of electric current.
(b) The values showed by Pinki here is a great concern and love towards her own 4 years old daughter.

The particles of water become more lighter and rise up in the middle. Due to this, the cold particles of water which are heavier come down along the sides of the vessel. So, the convection currents of heat are setup and water becomes hot. The moment, when the heat is applied at the top, then the water present in the upper portion becomes hot and these hot water molecules get fixed over the surface. Since, water is a bad conductor of heat, due to which water present at the lower end (or bottom) of the vessel remains.

(a) A flower is the reproductive part of plant which helps in sexual reproduction.
A flower ensures the occurrence of process of fertilisation.
(b) Yes, flower aids in both pollination and fertilisation. Different colours and fragrance of flowers attract insects to them causing dispersal of pollen grain ensuring pollination.
Fertilisation occurs in the ovary of the flower after pollination of male and female parts.
(c) Number of some flowers can either have male or female parts on them, these flowers are called unisexual.
Some flowers have both, the male and female parts on them so they are called bisexual flowers.
(d) Ravi is aware, sincere, helpful as he helps others and knowledgeable while his sister is inquisitive, ready to acquire new knowledge and observant.

(a) Typhoid and cholera.
(b) In vermi-composting toilets, human excreta is treated by earthworms in a pit.
(c) He is intelligent and concious about health

(a) Convex mirror is a mirror which is used as a rearview mirror. It is used to get a wide view of traffic behind.
(b) The values exhibit by Namit here is courtesy concerned for other, sympathy, knowledgeable.

In first saree, one thread which burnt with a smell of burning hair is from pure silk, silk and hair are protein fibres. So, on burning these threads, a smell of burning hair comes out. In second saree, second thread which burnt with the smell of burning cotton and paper because cotton and paper both are carbohydrates and on burning they give similar smell.

(a) Sachin noticed the disturbance in the water cycle in his area like stream drying up. Pond water getting muddy, less availability of fuel wood, etc.
(b) Deforestation.
(c) Love for nature and environmental consciousness.

(a) Chemical reaction between copper sulphate solution and iron metal. In this reaction, blue colour of copper sulphate solution changes to light green colour due to the formation of iron sulphate.
Copper sulphate + Iron \(\longrightarrow\) Iron sulphate + Copper
(Blue)                    (Grey)       (Light green)     (Brown)
(b) When baking soda and vinegar are mixed together then a chemical change takes place and bubbles of carbon dioxide gas are formed along with some other substances.
Baking soda              +                Vinegar          \(\longrightarrow\)     Sodium acetate + Carbon dioxide + Water
(Sodium hydrogen carbonate)   (Acetic acid)
(c) Explosion of a firework produces heat, light, sound and unpleasant gases. Explosion of a firework is a chemical change.

The contamination of soil with waste materials especially used polythene bags and plastics, pesticides, fertilisers, acid rain industrial chemical wastes, etc., is called soil pollution
Pesticides are the poisonous chemical substances which are sprayed on standing crops to save them from the harmful insects and diseases. Some of these pesticides also mix up with the soil in the fields and pollute it. The grains, fruits and vegetables grown in this polluted soil contain pesticides. When we eat such contaminated grains, fruits or vegetables, the pesticides present in them damage our health also.

(a) This process is known as crop rotation. All the plants/crops grown in soil use the minerals present in soil for their own use. This continuous usage depletes the concentration of mineral in soil.
(b) After growing leguminous plants, the mineral content of soil is restored and enriched to new level. Yes, the benefit of leguminous plant is the re-enrichment of soil minerals.
(c) Asha is observant, sincere and interested in applying her knowledge to situations.