The various factors responsible for grain loss during storage are:
(i) Biotic factors: Insects, Rodents (mice), Birds, Fungi, Bacteria, Mites, ect.
(ii) Abiotic factors: Inappropriate temperature, moisture, moisture contents of seeds, dampness of storage godown ect.
The above factors cause loss in weight, degradation in quality, discolouration of produce ect.
Measures for safe storage of grains: 
(i) Drying: Grains to be stored ideally should contain below 9% water content/moisture. When grains are harvested, usually contain 15 to 35% moisture. These freshly harvested grains are dried under the sun and then in shade to reduce the moisture content. Commercially grains are dried by mechanical driers with hot air blowing process.
(ii) Maintenance of hygiene: Grains should be kept in godowns that
(a) are very clean and do not have garbage, refuse, webs etc.
(b) do not have cracks, holes in walls, floor and ceilings.
(c) have clean and fresh gunny bags or are well treated with fumigate or dried under sun.
(d) have earthen pots, if to be used for storage, well cleaned and properly exposed to sun before use.
(iii) Prophylactic treatment: Godowns, gunny bags to be used for storage must be properly treated with fungicides, insecticides and other required pesticides by dusting, spraying or fumigation. Insecticides and fungicides should be mixed with grains that .are to be used for seed sowing.
(iv) Use of improved structures: Structures such as Pusa Bin, Pusa Cubicle, Pusa Kothar and Pant Kuthla can be used for storage purpose.
(v) Treatment of the surface area of the store house should be done by spraying mixture of BHC WP (50%), Pyrethrum (2.5 EC) and Malathion (50 EC) for controlling pests.
(vi) Fumigation of the store houses by chemicals such as aluminium phosphide tablets should be done.

Time period. The time taken by an oscillating body to complete one oscillation is called its time period. It is denoted by T. Its SI unit is second (s).
Frequency. The number of oscillations or vibrations completed by an oscillating body in one second is called its frequency. It is denoted by v (Greek letter nu).
SI unit of frequency=per second (s^-1) = cycles per second (cps) = hertz (Hz).
Relation between time period and frequency:
Let T=time period of an oscillating body. Then number of oscillations completed in T second = 1
Number of oscillations completed in 1 second =\(\frac { 1 }{ T } \)
But number of oscillations completed in 1 second = frequency (v)
∴ \(v=\frac { 1 }{ T } \)
Hence frequency is equal to the reciprocal of time period.

(a) Heat energy produced in the engine into K.E. of the car.
(b) Electric energy into potential energy
(c) Electric energy into mechanical energy
(d) P.E. into K.E.
(e) Electrical energy into heat and light.
(f) Electrical energy into sound energy.
(g) Chemical energy into heat energy and light.

Difference between mass and weight:

(a)  Measurement of force from Newton's second law. Suppose a force F acts on a body of mass m and changes its velocity from u to v in t seconds. Then
Initial momentum of the body, \({p}_{1}=mu\)
Final momentum of the body,  \({p}_{2}=mu\)
Change of momentum  \(= {p}_{2}-{p}_{1}=mv-mu=m\left(v-u\right)\)
Time taken \(= t\)
\(\therefore\) Rate of change of momentum  \(= \frac {Change \ of\ momentum} {time \ taken} = \frac {m\left(v-u\right)}{t}=ma\) 
Where a  is the acceleration of the body.
According to Newton's second law, the rate of change of momentum is directly proportional to the applied force, so
 \(F \infty \ ma.\)             or F = kma
Where k is constant. The unit of force is so chosen that k is equal to one. If m = 1, a = 1 and F = 1, then
1 = k. 1. 1    or  k = 1
F = ma     or   \(Force = Mass \times Acceleration.\)  
So a unit force is that force which produces a unit acceleration in a body of unit mass.
(b) The S.I. unit of force is Newton. One Newton is that force which produces an acceleration of \(1 m/ {s}^{2}\) in a body of mass 1
1 newton \(= 1 kg \times 1 m/s^2\) or \(1N = 1 kg m/s^2\)  
Thus, the second law of motion gives us a method to measure force. If the mass and acceleration of a body are known, we can determine the force acting on it.

Non-uniform motion .If an object covers unequal distances in equal intervals of time,it is said to be in non-uniform motion. Most of the motions seen in our daily life are non-uniform. For example,if we drop a ball  from the roof of a building we will note that the ball covers 4.9 m in the 1st second 14.7 m in the 2nd second 24.5 m in the 3rd second , and so on That is the ball covers increasingly larger distances in successive seconds as it falls down. Thus, the motion of a freely falling body is non-uniform
Other examples of non-uniform motion:
(i) A stone dropped from the top of a building
(ii) A ball thrown vertically upwards
(iii) The motion of a train as it leaves the station
(iv) The motion of a bus as it approaches a bus-stop
(v) The motion of a ball rolling down an inclined plane.

Plants and Animals differ as given in the table below:

(i) We will give ORS (Oral Rehydration Solution) from time to time till we reach to doctor or doctor comes to attend the patient. ORS is available in powder form packed in sachets.
(ii) We can make ORS in home by the following way:
Ingredients
1. One level teaspoon of salt
2. Eight level teaspoon of sugar
3. One litre of clean drinking or boiled water and then cooled (5 cupfuls-each cup about 200 .ml.),
Preparation Method
Stir the mixture till the salt and sugar dissolve.
(a) Arrange community lectures, debates to sensitise harmful effects of dehydration of the body.
(b) Conveying importation of ORS and its preparation in home

(i)Cathode rays travel in straight lines and thus cast shadows of objects placed in their path.
(ii)Cathode rays possess material particles because they can rotate a light paddle wheel placed in their path.
(iii)They are deflected towards positive plate thus showing that theses are negatively charged particles knowns as electrons
(iv)They ionise  gas through which they pass
(v)They are deflected by magnetic fields.
(vi)The nature of cathode rays is independent of the material of cathode.Hence they are common constituents of all matter
(vii)They can penetrate through thin metallic sheet
(viii)They can produce X-rays
(ix)The mass of a cathode ray particle is very-very small as compared to the mass of the atom from which it is formed

Comparison of properties of a true solution, colloidal solution, and suspension

Test of a colloidal solution or a suspension.
(i) A colloidal solution is turbid and particle settles down on adding a salt. In a suspension, particles settle down on keeping under the influences of gravity.
(ii) If the particles in a heterogeneous and opaque solution can be seen with naked eyes and get settled on keeping, then it is a suspension.
(b) (i) decrease of temperature
(ii) Increase of temperature.

The pressure exerted by a gas is the force exerted by gas particles per unit area on the walls of the container.It is expressed in pascal(Pa).1 atmosphere= \(1.01\times { 10 }^{ 5 }\) Pa.The pressure depends on the average kinetic energy of the colliding particles which depends on temperature of the gas.

(t) Let the two bodies have masses m) and mz and they are placed at the same distance R from the centre of the earth. According to the question, if the sameforce  acts on both of them, then
\({ F }_{ 1 }=\cfrac { GM{ m }_{ 1 } }{ { R }^{ 2 } } \)
and \({ F }_{ 2 }=\cfrac { GM{ m }_{ 2 } }{ { R }^{ 2 } } \)
As, F₁=F₂
Hence,\(\cfrac { GM{ m }_{ 1 } }{ { R }^{ 2 } } =\cfrac { GM{ m }_{ 2 } }{ { R }^{ 2 } } \)
So, m₁ = m₂, their masses will be same
(ii) Mathematically,\(g=\cfrac { GM }{ { R }^{ 2 } } \)
where, g= acceleration due to gravity
G = universal gravitational constant
M = mass of the earth
and R = radius of the earth 
(ii) G is known as the universal gravitational constant because its value remains same all the time everywhere in the universe, applicable to all bodies whether celestial or terrestrial.

(a) Take a tiny crystal of dry blue ink.Ink is a matter.Dissolve it in 100mL water.The colour of water becomes blue.Dilute 1mL of this blue water with 99mL clear water.Water again becomes blue though intensity of colour decreases.Repeat 2-3 times.The solution obtained remains coloured through intensity of colour decreases gradually.This shows that one tiny crystal of link contains millions of ink particles which are very very small
(b) Add 2g salt in a cylinder containing water marked at 100mL.Salt dissolves and disappears but the volume of water remains at 100 mL mark.This means salt particles get into spaces between water particles.Water is a matter and particles of water have spaces between them.
(c) Put a drop of perfume in one corner of the room.Stand at the other end.Stil you will get smell of perfume.This is because of matter, i.e., perfume are moving with air
(d) In the above case particles of perfume and that of air intermix with each other.This intermixing of particles of two different types of matter on their own is called diffusion.
(e) Open a water tap.Try to break the stream of water with your fingers,You will find that the stream of water does not cut.This is because particles of matter attract each other with a force that keeps the particles together.

(a) In composite fish culture system a combination of 5 or 6 fish species is used in a single fish pond. These species are selected so that they do not compete for food among themselves having different types of food habits.
(b) The combination of 6 species of fish in composite fish is highly advantageous because
(i) These fishes do not compete for food among themselves as they are having different types of food habits.
(ii) Secondly, food available in all the parts/zones of the pond is utilized due to different food habits.
(i) Demerit: One problem with composite fish culture is that many of these fishes breed only during monsoon. The fish seed collected can be mixed of these fishes breed only during monsoon. The fish seed collected can be mixed with that of other species. Thus, a major problem in fish farming is the lack of availability of good quality seeds.
(ii) This problem is overcome by breeding fish in ponds using hormonal stimulation. This ensures the supply of pure fish seed in desired quantities

It is very necessary to replenish forests for the following reasons:
(i) Rainfall: Trees give out enormous amount of water during transpiration. This water vapour helps in the formation of rain clouds. If trees are destroyed and not replenished the rainfall in the area will reduce. This may lead to less number of trees to grow.
(ii) Soil erosion: If trees are cut at a large rate the soil becomes barren. The top soil which is rich in organic matter will be washed away by water or carried away by wind. Thus reduction in rainfall and soil erosion may lead to the formation of desert.
(iii) Carbon dioxide-oxygen balance: Forests have very large number of trees. They give out \({ O }_{ 2 }\) and take in \({ CO }_{ 2 }\) in day time by the process of photosynthesis. Thus they help in maintaining carbon dioxide-oxygen balance in the atmosphere.

1. The tissue-specificity of the infection leading to very general-seeming effect is seen in case of HIV infection.In this case, HIV infecting virus goes to the immune system and damages its functions.Therefore, body cannot fight off the many minor infections that we face daily.
2. For example, small cold can become pneumonia; a minor gut infection leads to major diarrhoea with blood loss.These and other such diseases may cause death of HIV-AIDS patient.Thus, the other infections kill people that are suffering from HIV-AIDS.
3. The tissue-specify of the infection is lymph nodes.General seeming effects are loss of immunity to even minor other diseases or other minor infections that lead to death of the patient.

(i) The value of g depends on
(a) shape of the earth,
(b) rotation of the earth,
(c) altitude, and
(d) depth.
(ii) Acceleration due to gravity decreases.
(iii) The value of g decreases due to rotation of the earth.

Third equation of motion. Let a body start with initial velocity u and after covering distance s under uniform acceleration a, its velocity v in t seconds.Then 
Average velocity = \(\frac { u+v }{ 2 } \)
So the distance covered in time t is given by
s = Average velocity xTime = \(\frac { u+v }{ 2 } Xt\)
v + u = \(\frac { 2s }{ t } \) 
Using the first equation of motion : v = u+at or v - u = at
Multiplying equations (i) and (ii) ,we get 
(v+u) (v-u) = \(\frac { 2s }{ t } \) x at or  
\(v^{ 2 }-u^{ 2 }=2as\) 

Difference between Bryophyta and Pteridophyta:

Bohr and Bury gave the following rules for the distribution of electrons around the nucleus.
(i)Electron ar revolving around the nucleus in different orbits or shells.hese energy shells are represented by numbers 1, 2, 3, 4 or K, L, M, N.
(ii)The maximum number of electrons in any shell cannot exceed 2n², where n is the number of that energy level.Thus for
K-shell, n=1, no. of electrons=2x1²=2
L-shell, n=2, no. of electrons=2x2²=8
M-shell, n=3, no. of electrons=2x3²=18
N-shell, n=1, no. of electrons=2x4²=32
(iii)The outermost orbit of an atom cannot have more than 8 electrons and the next to the outer shell (penultimate shell) can have at the most 18 electrons.
(iv)It is not absolutely necessary that an orbit has its full quota of electrons before starting to fill the next higher orbit but the shells are filled in a stepwise manner.

(a) (i) centrifugation        
(ii) filtration
(iii) Separating funnel      
(iv) Evaporation
(v) Sublimation              
(vi) Winnowing
(b) (i) Physical change    
(ii) Chemical change
(iii) Chemical change      
(iv) Physical change.

(i) True finned fishes. mullets, bhetki, pearl spots.
(ii) Shellfishes. mussels, oysters and prawns.

(a) The symptoms and signs can tell that the baby is sick. Symptoms may be cough, loose motion, wound with pus, vomiting, etc, etc..y looking signs of disease on the basis of the symptom. Sign will give a little more definite indication of the presence of a particular disease.
(b) The sickness is determined by symptoms or indications that can be seen in the baby. The symptoms include vomiting, fever, loose motion, paleness in the body, etc.

When a wave propagates along the surface of a medium, it generally has both transverse and longitudinal components. When such a wave travels through the medium, its particles move either along a circle or an ellipse. Examples of such waves are:
(i) Seismic waves travelling along the surface of the earth during an earthquake or explosion.
(ii) Ocean waves in deep water.
(iii) Wave pulses produced by beetle's motion along the sand's surface.

The elongation produced in the string is due the weight of the stone. Since, the elongation decreases once the stone is lowered in water, it means some force acts on the stone in the upward direction. As a result, the net force on the string decreases and hence the elongation also decreases. This upward force exerted by water is known as the force of buoyance.

According to Archimedes' principle, the upthrust is equal to the weight of the fluid displaced by it. When the stoner gets fully immersed in water, the upthrust on it becomes maximum. Hence, no further decrease in the elongation of the string is observed.

Inertia of Direction. The inability of a body to change by itself its direction of motion is called 'inertia of direction'.
Examples:
(i) When a dog chases a hare, the hare runs along a zig-zag path. It becomes more difficult for the dog to catch hare because dog has more inertia of direction than that of the hare.
(ii) As a bicycle moves, the water drops sticking to its tire start leaving it tangentially.

Here t = 20s, v = 0, a = -1.5 \(m/s^{ 2 }\) , u=?
\(\therefore \) v = u + at
\(\therefore \) 0 = u-1.5 x 20 or u =1.5 x 20 = 30 m/s
So the intial velocity of the train = 30 m/s.

Thallophytes (algae), Bryophytes (moss) and Pteridophytes (ferns).
(i) They all have hidden reproductive organs.
(ii) They all have naked embryos (spores).

Viruses lack selectively permeable plasma membrane and cell organelles.

Thus they lack a basic structural organisation to perform various life processes effectively and in their own way.

After entering a living cell, a virus utilises its own genetic material and machinery of host cell to multiply.

(i) Molar mass of ammonia = 1 x 14 + 1 x 3 = 17 g
(ii) Moles of ammonia are present in the gas jar = \(\frac { 1.7 }{ 1.7 } \)=0.1 mole
(iii) Number of molecules of ammonia in the jar = 6.022 x 10²³ x 0.1
= 6.022 x 10²²

Homogeneous mixtures soda water,  air, vinegar, filtered tea.
Heterogeneous mixtures wool, soil.

The specific function of cardiac muscle is to contract and relax rhythmically throughout life.