► A bird has streamlined body.
► Its bones are light and strong.
► They are hollow and have air spaces between them.
► The hind limbs of birds are modified as claws, which help them to walk and to perch.
► The breast bones are modified to hold massive flight muscles which help in moving wings up and down
►  Birds have special flight muscles and the forelimbs are modified as wings.
► The wings and tail have long feathers which help in flying.

Thermos flask:
The thermos flask is an insulating storage vessel that keeps its content hot cooler than the surroundings for longer time.

Working:
(i) A thermos flask has double wails, which are evacuated.
(ii) It is silvered on the inside.
(iii) The vacuum between the two walls prevents heat being transferred from the inside to the outside by conduction and convection.
(iv) with very little air between the walls, there is almost no transfer of heat from the inner wall to the outer wall or vice versa inner wall to the outer wall or vice versa 
(v) Conduction can only occur at the points where the two walls meet, at the top of the bottle and through an insulated support at the bottom
(vi) The silvered walls reflect radiated heat buck to the liquid in the bottle.

i) 90° into radian:
1⁰ = \(\frac { \pi }{ 180 } \)
90^O =\(\frac { \pi }{ 180 } \)x 90 = \(\frac { \pi }{ 2 } \)radian
ii) \(\frac { \pi }{ 6 } \) into degree
π radian = 180⁰
\(\frac { \pi }{ 6 } =\frac { 180 }{ 6 } \) = 30⁰

i. Due to high pressure at the bottom of the dam, the dam may be destroy or crack.
ii. So dams are made stronger and thicker at the bottom than at the top.

The multiple reflections take place in showrooms and saloons

Carbon dioxide, carbon monoxide, oxides of sulphur, oxides of nitrogen, chloro fluoro carbons, methane etc

1. It is a process for preservation of liquid food.
2. This method was invented by Louis Pasteur in 1862.
3. Milk is heated up to 70⁰c to kill the bacteria and it is cooled to 10⁰c to prevent the growth of remaining bacteria.
4. Then milk is stored in sterilized bottles in cold places.

(i) The molecule of a substance that contains two or more atoms of different elements combined together in a definite ratio is called as a compound.
(ii) (ex) CO₂, H₂O

Respiration is the process in which energy is released while food is oxidised. It consists of external respiration and internal respiration.

Claviceps purpunya is the hallwcinogenic fungi causes greatest damage to the frustrated youth by giving unreal, extra ordinary lightness and hovering sensations.

(i) Computer is an electronic device that process the data and information according to our needs.
(ii) It follow instructions, called programs which determine the tasks the computer will perform.

Prokaryotic cell lacks a distinct nucleus and membrane bound organelles
eg: bacteria.

Characters of Pteridophytes:
1 Pteridophytes are the first true land plants with xylem and phloem. Hence it is called vascular cryptogams.
2 Pteridophytes exhibit alternation of generation. The diploid sporophytic phase alternates with the haploid gametophytic phase.
3 The main plant body is sporophytes, which is the dominant phase, differentiated into true root, stem and leaves.
4. Sporophytes reproduce by means of spores. Spores are produced in sporangium.

Disease causing micro organisms are called pathogens.
Pathogenic organisms are of 5 types :
i) viruses
ii) fungi
iii) worms
iv) bacteria
v) protozoa

Refractive index of the medium is the ratio of the speed of light in the air to the speed of light in that particular medium.
μ = \(\frac { Speed\ of\ light\ in\ air\ (c) }{ Speed\ of\ light\ in\ the\ medium\ (v) } \)

From Boyle's law :- P α 
Initial Pressure P₁  = atmospheric pressure + pressure of liquid cloumn
= Hρg + Hρg
Where h 2 depth of the pond
H 2 Assume 10m of water
V₁ = \(\frac { 4 }{ 3 } \pi \)r³ ; P₂ = Hρg
V₂ = \(\frac { 4 }{ 3 } \pi \)(3r)³ = \(\frac { 4 }{ 3 } \pi \)(27r³)
P₁V₁ = P₂V₂ 

​​​​​​​h+10 =10x27
h =270-10
depth of the pond, h = 260m

The fusion of Male and Female gametes (sperm, ovum) is called fertilization. In human, fertilization occurs in fallopian tubes of women's ovary.

Law of conservation of mass states that during any chemical change, the total mass of the products is equal to the total mass of the reactants".

Nitrogen reacts with non-metals like hydrogen, oxygen etc at high temperature to form their corresponding nitrogen compounds
\( 3 \mathrm{H}_{2}+\mathrm{N}_{2} \stackrel{\Delta}{\longrightarrow} 2 \mathrm{NH}_{3} \)

Uses of electroplating:
(i) Zinc is deposited over Iron by electroplating to protect it from corrosion and rust formation. It is used in automobile industries.
(ii) Wheel rims, car parts, bath taps etc. requires a non-corrosive, non-scratchy, shiny metal. Chromium suits well but it is expensive. So they are made from a cheaper metal and a coating of chromium is deposited over it by electroplating.

Three types ofheat transfer:
(i) Conduction
(ii) Convection
(iii) Radiation.

\(\frac { C-10 }{ 100 } =\frac { F-32 }{ 180 } =\frac { K-273 }{ 100 } \)

i. Decreases the pressure.
ii. Increase the area of contact

Parabolic mirror.

Chemical reactions carried out by light are called photolysis.

i. They respond to heat, chemicals, and radiations.
ii. They show irritability.

Elements which show the properties of metals as well as non metals are called metalloids

The shortened form of the name of are element is called its symboL

(i) Application software is a program or a group of programs designed for the benefit of end user to work on computer.
(ii) Examples of application program: Video player, Audio player, Word processing Software, Drawing tools etc.

When aseptate without (cross wall) mycelium contains many nuclei it is called as coenocytic mycelium.

Radius of curvature = 20 cm
Focal length (f) =\(\frac { Radius\quad of\quad curvat }{ 2 } \)
=\(\frac { R }{ 2 } =\frac { 20 }{ 2 } \)=10 cm

K = C + 273
K = 80 + 273
K = 353 kelvin

Metabolism is the sum total of the biochemical reactions involves in release and utilization of energy or energy exchange within the organisms.

► Th foetus consists of multitude of cells of different shape, size and content.
► Foetal cells gradually attain change in structure and function.
► This process is known as cell differentiation.

Antibiotic:
Penicillin, Neomycin, Gentamycin, Erythromycin are some antibiotics obtained from fungi which cure variable diseases.
Food:
Mushroom contains rich protein and minerals Common edible mushroom is Agaricus

The naming of an organism with two words are known as Binomial nomenclature.
Eg: Mangifera indica - Binomial name of mango
Mangifera - Genus name: indica - Species name

MMR Vaccine for measles, Mumps, Rubella, BCG (Bacille Calamette Guerin) vaccine for Tuberculosis

i) Plasmodium
ii) Paramecium
iii) Euglena

Photosynthesis is an irreversible change. In photosynthesis carbondioxide and water react in the presence of sunlight to produce a new substance called starch. Hence photosynthesis is a chemical reaction

Any unwanted change in physical, chemical and biological properties of the environment is termed as pollution.

i) Metalloids are all solid at room temperature.
ii) Metalloids can form alloys with other metals.
iii) The physical properties of metalloids tend to be metallic but their chemical properties tend to be non-metallic

I feel hotness. When an iron nail is hammered into a wooden plank, heat is liberated due to friction.

Personal hygiene habits:
(i) Shower or bath daily.
(ii) Always wash your hands before and after meals.
(iii) Keep fingernails clean and dipped.
(iv) Wash your teeth and mouth before and after each meal.
(v) Avoid touching your face, nose or mouth while preparing food.
(vi) Avoid coughing or sneezing around food and close your mouth by using hand kerchief while you cough in public places.
(vii) If you are to taste the food, use a clean spoon.
(viii) Change your clothes regularly and wash them cleanly especially undergarments.
(ix) Don't defecate in open field. Use clean toilets for defecation.
(x) If you are not well, avoid self-medication consult a doctor.

Streamlined body
(i) A streamlined body is the shape of the body that reduces resistance when moving
(ii) Streamlined bodies often have a teardrop shape.
(iii) Streamline shape reduces the friction of movement to a minimum thus decreasing overall drag
(iv) Streamlined body of birds help the particles of air to move upload them quickly and come together smoothly on the other side. The air does not provide much resistance to the body so that they can fly easily in air spending less energy.
(v) Streanilined body of fishes help them to move smoothly with the flow of water. Its body shape reduces friction while moving in water. It helps in the orientation of the fish movements in a particular direction.

i) During night photosynthesis does not occur. So, tree will not release oxygen and take in oxygen.
ii) Trees respire and they take in oxygen and release carbon dioxide. Due to their huge size, they take up comparatively more Oxygen than a human being. So, we will not get sufficient oxygen under a tree during night. It may cause breathing problems and suffocation. So it is bad for health.

Electroscope:
An electroscope is a scientific instrument used to detect the presence of electric charge on a body.
Types:
There are two types of electroscope.
a) Pith-ball electroscope
b) Gold-leaf electroscope.
Principle:
It works on the principle that like charges repel each other.
Structure of a gold leaf electroscope:
It is made up of a glass jar. A vertical brass rod is inserted into the jar through a cork. The top of brass rod has a horizontal brass rod or a brass disc. Two gold leaves are suspended from the brass rod inside the jar.
Working -
i) If a negatively charged object is brought near the top disc of the electroscope, it causes free electrons in the electroscope to move down into the leaves, leaving the top positive. Since both the leaves have negative charge, they repel each other and move apart.
ii) If a positive object is brought near the top disc of the electroscope, the free electrons in the electroscope start to move up towards the disc. The bottom has a net positive charge. The leaves repel other and move apart.

(b) Steel > Water > Wood is the correct statement
Steel has more number of free electrons than water and wood. So it is more electropositive. It has the tendency to gain electrons. So the thermal conductivity of steel is more than water and wood. Like wise, the thermal conductivity of water is more than that of wood.
Thermal conductivity of steel - 43 w/mK
Thermal conductivity of water - 0.606 w/mK.
Thermal conductivity of wood - 0.17 w/mK.

Components required:
Battery, Ammeter, Lamp (Bulb)
Procedure:
i. Connect the battery, ammeter and the lamp in series as shown in the figure.
ii. Note the ammeter reading.
iii. It is the current in the circuit.

i. The level of mercury is initially at the same level.
ii. The gas present in the manometer event pressure.
iii. The mercury level moves down in one limb and rises in other limb.
iv. The mercury level moves down in one limb and rises in other limb.
v. The difference in liquid pressure is measured.

i. Provide a wider field of view as they are curved outwards.
ii. Used in vehicles as rearview mirrors.
iii. Used in hallways of various buildings like hospital, hotels, schools, and stores.
iv. Mounted on a wall or ceiling where there are sharp turns.
v. Used on roads where there are sharp curves and turns.

Biological effects:
a) Spoilage of food and Vegetables:
i. Food spoilage may be defined as any change that causes food unfit for human consumption.
ii. The chemical reactions catalysed by the enzymes result in the degradation of food quality.
iii. It develops bad tastes, odour, deterioration and loss of nutrients.
iv. (eg.) 1. Rotten eggs develop a bad smell due to the formation of hydrogen sulphide gas.
v. (eg.) 2. Decaying of vegetables and fruits due to microbes.
b) Rancidity of fishes and meat:
i. Fishes and meat contain high levels of polyunsaturated fatty acids.
ii. When exposed to air or light these polyunsaturated fatty acids undergo oxidation causing bad odour.
iii. This process is known as rancidity.
c) Apples and fruits turn brown when cut:
i. The cells of apples, fruits and other vegetables contain an enzyme called poly phenol oxidase or tyrosinase.
ii. This enzyme when comes in contact oxygen catalyses a biochemical reaction of plants phenolic compounds to brown pigments known as melanins.
iii. This chemical reaction is browning.

A. Traditional Techniques:
i. Fermentation: Fermentation is the microbial conversion of starch and -sugar into alcohol. It makes foods more nutritious and palatable
ii. Pickling: It is of two types
1. Chemical pickling: Food is placed in an edible liquid that kills bacteria and other microorganisms, Eg; Vinegar, alcohol, vegetable oil.
2. Fermentation Pickling: Bacteria in the liquid produce organic acid as preservation agent that produces lactic acid due to the presence of Lactobacillus.
iii. Boiling: Boiling liquid food items kill all the microbes eg; Milk & water
iv. Sugaring: Sugar is used to preserve fruits in an antimicrobial syrup with fruit such as. apple, pears, peaches.
B. Modern techniques:
i. Pasteurization
1. It is a process for preservation of liquid food.
2. Milk is heated upto 700c to kill the bacteria and it is cooled to 100c to percent the growth of remaining bacteria.
3. Then Milk is stored in sterilized bottles in cold places.

(i) It is the structural and functional unit of life.
(ii) Cells are often called as building blocks of life.
(iii) Cell consists of cytoplasm enclosed within them a membrane,
which contains many biomolecules, such as protein and Nucleic acids.
(iv) Cells vary in shape and size.
(v) There is a central nucleus and a living cell organelles like endoplasmic reticulum, mitochondria, Golgi bodies, centrioles, ribosome, lysosome, etc. present in an animal cell.
(vi) Each cell organelle performs a specific function

Burning fossil fuels is a cause of global warming because it produces Co, and methane. These gases give the greenhouse effect. This increase the Earth's average temperature and results in the phenomenon called Global warming.

_wμ_g = \(\frac { Refractive\ index\ of\ glass }{ Refractive\ index\ of\ water } \)
\(=\frac { \frac { 3 }{ 2 } }{ \frac { 4 }{ 3 } } =\frac { 9 }{ 8 } \)=1.125

We need to round off the number to two decimal places. So, the last digit to be kept is 6. Since the next digit is more than 5, we should increase the second digit by one. So, the answer is 1.87.

Heat energy required Q = 1000 J
Raise in temperature T = 20^oC
Heat capacity C' = ?
\(\mathrm{C}^{\prime}=\frac{\mathrm{Q}}{\Delta \mathrm{T}}=\frac{1000}{20^{\circ}}=50 \mathrm{~J} /{ }^{\circ} \mathrm{C}\)
Heat capacity of the iron ball is 50 J/^oC.