Fish liver oil are of great medicinal value and are rich in vitamin A, D and E.
Liver oil of cod, Tuna, Halibut and shark, yield these oils.

Triple antigen is a combined vaccine for protection against Diphtheria, Pertussis (whooping cough) and Tetanus.

At home, we can conserve water by
1. Using a bucket of water to take bath than taking a shower.
2. Using low flow taps.
3. Using recycled water for lawns.
4. Repairing the leaks in the taps.
5. Recycling or reusing water wherever it is possible.
At school we could save water by
1. Collecting roof top water through, Rain water harvesting methods .
2. Creating awareness on water conservation by sticking poster-s.of slogans near the taps.
3. Using recycled water for lawns.
4. If not using any tap turn it off.
5. Report leaks. Make it a classroom activity to check for leaks regularly.
6. Bring a water bottle to school, At the end of the day, any leftover water can be poured onto the garden.

1. The first four planets Mercury, Venus, Earth and Mars are relatively close together and close to the Sun. They form inner solar system and so they are called as inner planets .
2. They have a surface of solid rock crust and so are called terrestrial or rocky planets .
3. Their insides, surfaces and atmospheres are formed in a similar way and form similar pattern.

The number of vibrations (complete waves or cycles) produced in one second is called frequency. Its SI unit is hertz.

Before the body is immersed,
The weight of water and jar = 700 grams.
A body of volume 100cc is immersed in water in the jar.
The weight of body = 100 grams.
Because 1cc = 19m.
(Since 51 unit for volume is 1m3 = 1000000 grams or 1000000 cc)
The weight of the water and jar after immersion = 700g + 100g = 800g or 0.8kg.

1. Use and throwaway plastics cause short and long term environmental damage.
2. Half of all the plastic items made today is used for throwaway plastic items.
3. They block drains and pollute water bodies .
4. One-time use plastic causes health problems for humans, plants and animals.
5. If these items are thrown away they can stay in our environment for over 1000 years causing plastic pollution for future generations.
6. Some examples are plastic carry bags, cups, plates, straws, water pouches etc.

Pascal's Law states that the external pressure applied on an incompressible liquid is transmitted uniformly throughout the liquid.

a) Both assertion and reason are true and reason is the correct explanation of assertion.

d) Assertion is false but reason is true.

A body moving in an orbit around a planet is called Satellite.
They are two types.
i) Man made or Artificial Satellites
ii) Natural Satellites.

The Sun and celestial bodies which revolve around it form the solar system.

1. The crop supply to the field micro and macronutrients required for a crop growth in a field.
2. It gives the NPK (Nitrogen, Phosphorus, potassium).

Friedrich Wohler

When we put the ice cube in a glass of water it will float because density of ice cube is lesser than water. So it will float.
When we put the ice cube in a glass of alcohol it will sink because density of ice cube is greater than alcohol. So it will sink.
Density of water = 1 g cm^-3
Density of ice cube = 0.917 g cm^-3
Density of alcohol = 0.789 g cm^-3

Advantages of hydroponics:
1. Conservation of water and nutrients.
2. Controlled plant growth.
3. In deserts and Arctic regions hydroponics can be an effective alternative method.
4. Hydroponics is the method of growing plants without soil, using mineral nutrient solutions in water.
5. Hydroponics is successfully employed for the commercial production of seedless cucumber and tomato.

In one such disease, there is a progressive decrease in WBC of the patient.
a) Name the disease and its causative agent.
Name of the disease : AIDS
Causative agent :. HIV - Human immuno deficiency virus
b) Name the type of WBC affected during infection.
Type of WBC affected by HIV : T-Iymphocytes
c) How does the blood of a patient come in contact with blood of healthy patient?
Mode of Transmission : Sexual contact, transfusion of unscreened blood, by surgical equipments from infected mother to the foetus.
d) Suggest three methods that help in preventing such infection.
Prevention :
1. Disposable syringes and needles should be used .
2. Protected and safe sexual contact.
3. Screening of blood before blood transfusion .
4. Avoid sharing shaving blades/razors.

1. Carbon occurs in various forms on earth. Charcoal, diamond and graphite are elemental forms of carbon. Combined forms of carbon include carbon monoxide, carbon dioxide and carbonate salts. All living organisms are made up of carbon containing molecules like proteins and nucleic acids.
2. The atmospheric carbon dioxide enters into the plants through the process of photosynthesis to form carbohydrates.
3. From plants, it is passed on to herbivores and carnivores. During respiration, plants and animals release carbon into atmosphere in the form of carbon dioxide.
4. Carbon dioxide is also returned to the atmosphere through decomposition of dead organic matter, burning fossil fuels and volcanic activities.

Planting more trees to reduce carbondioxide constant in the atmosphere.

Supporting Water - Purification Efforts:
1. Using the technology developed for the ISS, areas having water scarcity can gain access to advanced water filtration and purification systems.
2. This could very well be a life - saving difference for the people in such hazardous locations.
3. The water recovery system (WRS) and the oxygen generation system (OGS) developed for the ISS have saved a village in Iraq from being deserted due to lack of clean water.
Eye tracking technology:
1. The Eye tracking device, built for a microgravity experiment has proved ideal to be used in many laser surgeries.
2. This device tracks the eyes position very accurately without interfering with the surgeon's work.
3.Eye tracking technology is helping disabled people with limited movement and speech.
Robotic arms and Surgeries:
1. Robotic arms developed for research in ISS are providing significant help to the surgeons in removing inoperable tumours and taking biopsies with great accuracies.
2. Robotic arms do heavy lifting in Cancer treatment in the form of surgical robots.
3. ISS technology are useful in the development of improved vaccines, breast cancer detection and treatment, ultrasound machines for remote regions etc.

1. In Daniel cell zinc metal acts as anode and copper metal acts as cathode .
2. Aqueous zinc sulphate solution makes the anodic electrolyte. Whereas aqueous copper sulphate solution makes the cathodic electrolyte.
3. Saturated solution of potassium chloride (KCI) acts as salt bridge .
4. At anode, zinc undergoes oxidation losing its electrons .
. Zn_(S) ⟶ Z²⁺+ 2e^- (Oxidation)
5. At cathode, copper ions from cathodic electrolyte gain electrons at the surface of cathode and get reduced to copper metal.
Cu²⁺ + 2e^- ⟶ Cu_(S)(Reduction)
Net reaction,
Zn + Cu²⁺ ⟶ Zn²⁺ + Cu_(s)
6. Cell potential of Daniel cell is 1.1V

1. Musical instruments such as shehnai, trumpets and Nathaswaram, Mega phones, loud speakers uses the property of reflection of sound to guide most of the sound waves from the source in the forward direction towards the audience.
2. In stethoscopes, sound produced in the body reaches doctor's ears by multiple reflection of sound that happen in the connecting tube.
3. Echo is used to find the distance between two distance objects.
4. Ultrasound is used in examing inner parts of the body and also in marine surveying.
5. Ultrasound is used in cleaning technology, to detect cracks and flaws to form the image of the heart through 'echo cardiography'.
6. Ultrasound is employed to break stones formed in the kidney.
7. 'SONAR' is a device uses ultrasonic waves to measure the distance, direction and speed of the underwater objects.
8. In Electrocardiogram (ECG) the sound variation produced by the heart is converted into electrical signals, which represents the electrical activity of the heart muscle.

1. Catenation is binding of an element to itself or with other elements through covalent bonds to form open chain or closed chain compounds.
2. Carbon is the most common element which undergoes catenation and forms long chain compounds.
3. Carbon atoms links repeatedly to itself through covalent bond to form linear chain, branched chain or ring structure.

4. This property of carbon itself is the reason for the presence of large number of organic carbon compounds.
5. Ex: Starch, Cellulose contain chains of hundreds of carbon atoms.
6. Plastic we use in our daily life are macromolecules of catenated carbon compounds.

Velocity of sound = 340 ms^-1
Height of tower = 750 m
Total distance travelled = 2 x 750: 1500 m
\(Valocity=\frac {distance}{time}\) 
\(340=\frac {1500}{time}\) 
\(time=\frac {1500}{340}=4.4s\)
After 4.4 s, the splash is heard.