Functions of Mitochondria :
(i) Mitochondria is the main organelle of cell respiration. They produce a large number of ATP molecules. So they are called as power houses of the cell or ATP factory of the cell.
(ii) It helps the cells to maintain normal concentration of calcium ions.
(iii) It regulates the metabolic activity of the cell.

(i) Tidal energy does not produce any pollution.
(ii) It does not use any fuel and does not produce any waste.
(iii) Tides are predictable, so tidal energy can be produced at any time.
(iv) water is denser than air and therefore can generate electricity at lower speeds than wind turbines.

(i) Cancer is an abnormal and uncontrolled division of cells that invade and destroy surrounding tissue forming a tumor or neoplasm (new growth).
 

The two important properties of stem cells that differentiate them from other cells are:
(i) Its ability to divide and give rise to more stem cells by self-renewal
(ii) Its ability to give rise to specialised cells with specific functions by the process of differentiation.

Script editor is where you edit your programs or your sprite's pictures.
The script editor has three main parts:
(i) Script area: Where you build scripts.
(ii) Block menu: Where you choose the category of blocks (programming statements) to use.
(iii) Block palette: Where you choose the block to use.

TFM means Total Fatty Matter. It is the one of the important factors to be considered to assess the quality of the soap. Soap which have higher TFM, is a good bathing soap.

The Geological time scale is a system of chronological dating that relates geological rock strata to time, and is used by geologists, paleontologists, and other Earth scientists to describe the timing and relationships of events that have occurred during Earth's history.

A catalyst is a substance which increase reaction rate without being consumed in the reaction.

Sub critical: The mass of fissile material necessary to sustain chain reaction is called sub critical.
Super critical: The mass of the fissile material is more than the critical mass, is termed as super critical.

(i) Temperature of the substance rises.
(ii) The substance may change its state from solid to liquid or liquid to gas.
(iii) The substance will expand when heated.

The number of water molecules found in the crystalline substance is called water of crystallization

(i) Resolving power of a telescope is defined as the ability to distinguish between two objects distinctly which is placed at infinite distance.
(ii) Resolving power of a telescope \(\frac { D }{ 1.22\lambda } \).
(iii) D is the diameter/aperture of the objective lens, λ be the wave length of the light.
(iv) The resolving power is inversely proportional to wavelength and directly proportional to the aperture of the lens.

The elasticity of a solid is higher than a liquid or a gas and so sound travels faster in solids than in liquids.

The law of segregation states that "When a pair of contrasting factors or genes or allelomorphs are brought together in a heterozygote or hybrid, the two members of the allelic pair remain together without mixing and when gametes are formed, the two separate out, so that only one enters each gamete".

(i) The main significance of modem periodic table is it gives a clear understanding of the general properties and trends within a group or a period.
(ii) To predict with accuracy the properties of any element.

The formation of the sperm in male and the ovum in female is called gametogenesis. It involves spermatogenesis (formation of spermatozoa) and oogenesis (the formation of ova).

Animals posses two types of circulatory system. They are.
i. Open type
ii. Closed type
(i) Open type :  In open type the blood is pumped by heart into blood vessels that open into blood spaces called as sinuses. These sinuses are the body cavities which are called haemoceol. Capillary system is absent. E.g: Arthropods, Molluscs and Ascidians.
(ii) Closed type In closed type the blood flows in a complete circuit around the body through specific blood vessels. The blood flows from arteries to veins through small blood vessels called capillaries. E.g: Vertebrates

(i) If a force acting on a body of mass. 1 gram produces an acceleration of 1 cm s^-2, then the force is said to be 1 dyne.
(ii) 1 dyne = 1g cm s^-2, 1N = 10⁵ dyne

(i) Measurement of atomic mass of an element is somewhat more complicated since most of the elements exist as a mixture of isotopes, each of which has its own mass.
(ii) Thus, it is essential to consider this isotopic mixture while calculating atomic mass of an element.

(i) Respiration takes place by a pair of lungs, which are light spongy tissues enclosed in the thoracic cavity.
(ii) Each lung is enclosed by a double membranous pleura.
(iii) Atmospheric air passes through the external nostril and nasal passages into the pharynx. From the pharynx it passes through the glottis into the wind pipe.
(iv) The anterior part of the wind pipe is enlarged to form the larynx or voice box with its wall supported by four cartilaginous plates. Inside the larynx lies the vocal cord and its vibrations result in the production of sound.
(v) The larynx leads into trachea or wind pipe. Tracheal walls are supported by rings of cartilage which help in the free passage of air.
(vi) The epiglottis prevents the entry of food into the trachea through the glottis.
(vii) The trachea divides into two branches called the bronchi one entering into each lung and dividing into further branches called bronchioles which end in alveoli.

(i) In anaerobic respiration the amount of energy produced is very less.
(ii) Aerobic respiration is seen is humans wherein the number of ATP molecules produced from a glucose molecule is more than an aerobic respiration.

There are companies who are doing e-waste management an a commercial scale. Therefore organizations which generate a lot of e-waste must not throw the same in garbage bins but channelise the e-waste through the organizations meant for the same.

The following steps may help in controlling and prevent the spreading of HIV infection:
(i) Screening of blood from blood banks for HIV before transfusion.
(ii) Ensuring the use of disposable needles and syringes in hospitals and clinics.
(iii) Advocating safe sex and advantages of using condoms.
(iv) Creating awareness campaign and educating people on the consequences of  AIDS.
(v) Persons with HIV/AIDS should not be isolated from the family and society.

Plant materials brought into a country must be free from pathogens. It may lead to outbreak of new disease or introduction of a new pathogen into the environment. Thus plant materials (seeds / saplings) are tested in plant quarantine.

(i) Pictures and Audio-Visuals give us more understanding than teaching and writing on black board. So, any visual representation of the concepts would help us to understand better and make teaching simple
(ii) Yes. Visual Communication helps us to easily conceptualize complicated theorems and concepts. When the teacher shows pictures / videos that represent the concept, we would easily relate to its application and firmly understand the concept without any mis-perception
(iii) Pictures, Audio-Visuals, animations provide additional information and helps us to easily correlate the concepts. We could easily remember the visuals than black board writing, and visualize it, so that we do not forget and we could easily recollect at the time of examination.

Detergents are better than soaps because they,
(i) can be used in both hard and soft water and can clean more effectively in hard water than soap.
(ii) can also be used in saline and acidic water.
(iii) do not leave any soap scum on the tub or clothes.
(iv) dissolve freely even in cool water and rinse freely in hard water.
(v) can be used for washing woollen garments, where as soap cannot be used.
(vi) have a linear hydrocarbon chain, which is biodegradable.
(vii) are active emulsifiers of motor grease.
(viii) do an effective and safe cleansing, keeping even synthetic fabrics brighter and whiter.

(i) Growth hormone is produced by anterior to be of pituitary gland.
(ii) GH promotes the development and enlargement of all tissues of the body.
(iii) It stimulates the growth of muscles, cartilage and long bones.
(iv) It controls the cell metabolism The improper secretion of this hormone leads to the following conditions.
Dwarfism:
(i) It is caused by less secretion of growth hormone in children.
(ii) The characteristic features are stunted growth, delayed skeletal formation, retarded sexual development and mental disability.
Gigantism:
(i) Over secretion of growth hormone leads to gigantism in children.
(ii) It is characterised by overgrowth of all body tissues and organs. Individuals attain abnormal increase in height.
Acromegaly: Excess secretion of growth hormone in adults may lead to abnormal enlargement of head, "face,hands and feet.

Yes. When there is a change in the environment, the animals respond to the change. They develop adaptive structures. The characters developed by the animals during their life time, in response to the environmental changes are called acquired characters.
(i) Leo lived in the mountain region and it was wild. It developed hunting skills for survival and this made his legs and body strong. So the muscled physical body, strong legs and hunting skills were the acquired characters inherited by Leo.
(ii) According to Lamarck, the. acquired characters are transmitted to the offspring by the process of inheritance.

Reversible Reactions: A reversible reaction is a reaction that can be reversed, i.e., the products can be converted back to the reactants. A reversible reaction is represented by a double arrow with their heads in the direction opposite to each other. Thus, a reversible reaction can be kept

Explanation: The compound 'AB' undergoes decomposition to form the products 'A' and 'B'. It is the forward reaction. As soon as the products are formed, they combine together to form 'AB': It is the backward reaction
PCl₅(g) ⇌ PCl₃(g) + CI₂(g)
Irreversible Reactions: The reaction that cannot be reversed is called irreversible reaction. Consider the combustion of coal into carbon dioxide and water.
C_(s) + O_2(g) ⟶ CO_2(g)+ Heat
Coal oxygen Carbon dioxide
In this reaction, solid coal burns with oxygen and gets converted into carbon dioxide gas and water. As the product is a gas, as soon as it is formed it escapes out of the reaction container. It is hard to decompose a gas into a solid. Thus, the backward reaction is not possible in this case. So, it is an irreversible reaction

(i) Atom bomb is based on the principle of uncontrolled chain reaction.
(ii) In an uncontrolled chain reaction, the number of neutrons and the number of fission reactions multiply almost in a geometrical progression.
(iii) This releases a huge amount of energy in a very small time interval and leads to explosion.
Structure:
(i) An atom bomb consists of a piece of fissile material whose mass is sub critical.
(ii) This piece has a cylindrical void. It has a cylindrical fissile material which can fit into this void and its mass is also sub critical.
(iii) When the bomb has to be exploded, this cylinder is injected into the void using a conventional explosive.
(iv) Now, the two pieces of fissile material add up to form super critical mass which leads to an explosion.
(v) During this explosion tremendous amount of energy in the form of heat, light and radiation is released.
(vi) A very high temperature and pressure are experienced in fraction of second along with hazardous radiation like ૪ rays which adversely affect the living creatures.

Cubical expansion:
(i) If there is an increase in the volume of a solid body due to heating, then the expansion is called cubical or volumetric expansion.
(ii) As in the cases of linear and areal expansion, cubical expansion is also expressed in terms of coefficient of cubical expansion. The ratio of increase in volume of the body per degree rise in temperature to its unit volume is called coefficient of cubical expansion. This is also measured in K^-1.

(iii) The equation relating to the change in volume to the change in temperature is given below:
\(\frac { \triangle V }{ { V }_{ 0 } } \) = α_v ΔT
ΔV - Change in volume
V₀ - Original volume
ΔT - Change in temperature
α_v - Coefficient of cubical expansion.

(i) When a parallel beam of monochromatic (single coloured ) light passes through a gas or liquid or transparent solid, a part of light rays are scattered. This scattering is called Raman scattering (inelastic scattering).
(ii) Raman Scattering is defined as "The interaction of light ray with the particles of pure liquids or transparent solids, which leads to a change in wavelength or frequency".
(iii) The scattered light contains some additional frequencies (or wavelengths) other than that of incident frequency (or wavelength). This is known as Raman scattering or Raman Effect.
(iv) The modified lines are called 'Raman lines' and the unmodified lines are called as 'Rayleigh lines'. The lines having frequencies lower than the incident frequency is called stokes lines and the lines having frequencies higher than the incident frequency are called Anti-stokes lines.

(i) To analyse that the planets are irregular shaped objects, Doppler effect is applied.
(ii) Using Doppler effect, an electromagnetic wave or a high frequency sound wave can be made to incident on different points of planet's surface. By finding the frequency shifts of the reflected waves from different points on planets surface, one can analyse that the planet is made of hills and valleys. From this analysis, we can come to a conclusion the planets are irregularly shaped objects.
(iii) Jagadish Chandra Bose, a famous Indian scientist and Biologist, discovered that plants can feel sadness, happiness, pain etc., for that, he invented device named crescograph. The feelings of sadness, happiness, pain etc.. have different frequencies. When we touch a plant with a lovable thought, the frequency of that thought can be sensed by plants and trees.

Yes. Hirudin is used as an anticoagulant in medical science.

(i) Along the period, from left to right in the periodic table, the electronegativity increases because of increase in nuclear charge.
(ii) On moving down a group, the electronegativity of elements decreases because of increased number of energy levels.

(i) Acquired traits are the characters that cannot be passed from one generation to the next generation.
(ii) Characters which are inherited by the offspring from the parents and carried from one generation to another generation are called Inherited traits.

(i) Kalaivani's mother took a small PVC pipe which has water in it and held in a horizontal position. Water came out drop by drop. When she raised one of the ends of the pipe, the water through the other end came out with a greater speed. She said initially when I was holding the pipe in a horizontal position, pressure at the both the ends are same. So water did not come out. The difference in pressure (Pressure difference) between the two ends is zero. But when I raised one of the ends, the top end has high pressure, and the bottom end has low pressure. Due to this pressure difference, water came out with a faster rate. So compare a conductor or a wire to this PVC pipe The wire is connected to a battery, whose one end has higher potential and the other end has lower potential. Due to this difference in potential, electrons from negative terminal (lower potential end) flow towards the positive terminal (higher potential end). Here electron flow is compared with the water flow and the electric potential is compared with the pressure. Kalaivani felt very happy, after hearing her mother's genius explanation.
(ii) When Kalaivani asked how to understand about the concept of resistance from her mother's scientific explanations, her mother continued. If the water pipe is smooth inside, then there is no charge in the speed of flow of water. i.e., zero resistance. But when the pipe has some blocks inside at different points, the water changes its speed of flow at different points, likewise, whenever electrons flow inside the conductor, they may collide with each other, due to which their speed will be resisted (blocked), which forms as electrical resistance. Her explanation made Kalaivani satisfied.
(iii) When two resistors of resistances, R₁ & R₂ are connected in series to a battery source.
\({ R }_{ s }={ R }_{ 1 }+{ R }_{ 2 }\)
When R₁ & R₂ are connected in parallel,
\(\frac { 1 }{ { R }_{ p } } +\frac { 1 }{ { R }_{ 1 } } +\frac { 1 }{ { R }_{ 2 } } \Rightarrow \frac { 1 }{ { R }_{ p } } =\frac { { R }_{ 2 }+{ R }_{ 1 } }{ { R }_{ 1 }{ R }_{ 2 } } \)
\({ R }_{ p }=\frac { { R }_{ 1 }{ R }_{ 2 } }{ { R }_{ 1 }+{ R }_{ 2 } } \)

(i) Yes, it is necessary to take the blood reports for both boy and girl to ensure that he or she is free of any sexually transmitted diseases (STD) like syphilis, AIDS.
(ii) No, blood test report is necessary for both boys and girls living all over the world.

(i) Let M be the mass of the Earth and m be the mass of the object.
(ii) The entire mass of the earth is assumed to be concentrated at its centre. The radius of the earth is R (= 6378 km = 6400 km approximately).
(iii) By Newton's law of gravitation, the force acting on the object is given by
F = G M m / R²  ............. (A)
(iv) According to Newton's second law, the force acting on the object is given by the product of its mass and acceleration. Here acceleration of the is under action of gravity hence a =g.
F=ma =mg
F = weight = mg
Comparing equations (A) and (B), we get
g= GM/ R²
Acceleration due to gravity
g=\(\frac { GM }{ { R }^{ 2 } } \).

Blood Groups
(i) The concept of blood grouping was discovered by Karl Landsteiner. He identified blood groups A, B and O. AB blood group was recognized by Decastello and Steini.
(ii) Human blood contains certain specific substances called agglutinogens or antigens (Ag) and agglutinins or antibodies (Ab). Antigens are found on the membrane surface of RBC. Antibodies are present in blood plasma. Based on the presence or absence of antigen and antibodies human blood group is classified into four groups called A, B, AB, and O. An individual has one of the four blood groups.
(iii) 'A' group individuals: Antigen 'A' is present on the surface of RBC and antibody b (anti-b) is present in the plasma.
(iv) 'B' group individuals: Antigen 'B' is present on the surface of RBC and antibody an (anti-a) is present in the plasma.
(v) 'AB' group individuals: Antigens A and B are present on the surface of RBC and antibodies are absent in the plasma.
(vi) 'O' group individuals: No antigen A or B are absent on the surface of RBC. However, the plasma contains both antibodies 'a' and 'b' (anti a and b).
Blood donation :
(i) In blood transfusion one must consider the antigen and antibody compatibility (matching) between the donor and the person receiving blood (recipient). When an individual receives a mismatched blood group from the donor agglutination (clumping) of blood occurs in the body which leads to death.

The atomicity of an element can be derived using Avogadro's hypothesis. Let us consider the following equation

According to Avogadro's law, 1 volume of any gas occupy 'n' number of molecules.

if n = 1 then

(i) 1 molecule of hydrogen chloride gas is made up of \(\frac{1}{2}\) molecule of hydrogen and \(\frac{1}{2}\) molecule of chlorine
(ii) But 1 molecule of hydrogen chloride contains one atom of hydrogen and I atom of chlorine
(iii) Hence \(\frac{1}{2}\) molecule of hydrogen = 1 atom of hydrogen
(iv) Or 1 molecule of hydrogen = 2 atoms of hydrogen
(v) So the atomicity of hydrogen is 2, and molecular formula is H₂
Similarly,
\(\frac{1}{2}\) molecule of chlorine = 1 atom of chlorine 1molecule of chlorine = 2 atoms of chlorine So the atomicity of chlorine is 2, and its molecular formula is Cl₂

Beta decay.

Length of AI sheet, L = 30 m
Coefficient of linear expansion, Δl = 23 x 10^-6 K^-1
Change in temperature ΔT = 300 k
To find: Change in length ΔL =?
ΔL = L α_L ΔL
= 30 x 23 x 10^-6 x 300
= 2.07 x 10^-1
ΔL = 0.207 m

Power of convex lens, P₁ = + 6 D
Power of concave lens, P₂ = - 4 D
Power of combination of two lenses
P = ?
P = P₁ + P₂ = 6 - 4 = 2D
P = 2D.

Given
Speed of the train, V_s =30 rns^-1
Frequency of the train, n =600Hz
Speed of sound, v =340 ms^-1
To find: Apparent frequency n =?
Solution
\(n'=\left( \frac { v }{ v-{ v }_{ s } } \right) \times 600\)
\(=\frac { 340 }{ 310 } \times 600\)
Apparent frequency n' = 658 Hz

Given:
Current passing through heater I= 20 A
To find: Resistance of heating element R = ?
Solution
\(V=IR\Rightarrow \frac { V }{ I } =\frac { 220 }{ 20 } =11\Omega \)
Resistance, R = 11Ω

During impulse on first body:
Mass of the first body,
m₁ = 20 x 10^-3 kg
Time, t₁ = 4 s
Initial velocity, u₁= 0
Final velocity, v₁ =100 m/s
During impulse on second body:
Mass of the second body,
m₂ =10kg
Time, t₂ = 2 minutes
= 2 x 60 s = 120 s
To find: Final velocity, v₂ =?
Initial velocity, u₂ = 0
(i) Impulse on the first body,
F.t₁ =m₁(v₁-u₁)             [∵ u₁=0]
F.t₁ =m₁v₁
F.t₁ =20 x 10^-3 x 100
F.t₁ =2 x 10^-3 x 10³ =2 Js         .............(1)
(ii) Impulse on the second body
F.t₂ =m₂(v₂-u₂)        [∵ u₂=0]
F.t₂ =m₂v₂
Ft₂ =10 x v₂                    ...............(2)
Dividing al and CD, we get

Velocity of the second body, v₂ =6 m/s.

Number of moles = \(\frac{Mass}{Atomic \ mass}\)
∴ Mass = Number of moles x Atomic mass
= 0.5 x 16
= 8g.

Removal of parathyroid glands during thyroidectomy (removal of thyroid) causes decreased secretion of parathormone, The conditions are
(i) Muscle spasm known as Tetany.
(ii) Painful cramps of the limb muscles.

When we are pricked by a cactus, the sensory neurons are activated immediately. They take the message to the brain or spinal cord. The message given by the brain or spinal cord is brought back by the Motor neuron. The motor neuron carries the message to the hand muscles. We immediately pull our hand away from the cactus.