Because these breeds are fairly good with yielders and also useful for farm work. So they are called as dual purpose breeds.

Possible causes: Infected by the virus through, contaminated food and water and oral route.
Possible solution: Proper sanitation and hygiene in the babies family.

i) Availability of more water than needed.
ii) Water current may damage the plant body.
iii) Water levels may change regularly.
iv) Maintain buoyancy in water.

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.

No, he will not be able to hear the sound produced by his friend.

No, sound cannot travel through vacuum.
Because, sound can travel only when there are particles, which can be compressed and rarefied in the medium.

1. Covalent bonding is the sharing of electron between atoms. This type of bonding occurs between two atoms of the same element.
2. To form Ionic compounds carbon must gain four electrons forming C^4- anions but it would be difficult for its nucleus with six protons to hold onto ten electrons .
3. It could lose four electrons to form C⁴⁺ cations, but it would require a large amount of energy to remove four electrons .
4. These two conditions are highly unfavourable. Therefore carbon molecules share their four valence electrons through single, double, and triple bonds so that each atom can achieve noble gas configuration.

Helium in the balloon is lighter than the air around it, it receives an upward thrust known as buoyancy. Because helium weighs less than the amount of air it has displaced. So it floats.

a) Importance of green houses
1. Disease-free plants can be produced continuously.
2. Water requirement of the crop is very low
3. Yield is very high compared to outdoor cultivation.
4. A limited pesticide is needed.
5. It protects plants from uncertain weather.
b) Uzahavan mobile Application
Government of Tamilnadu has launched Uzhavan mobile application. It can be used by farmer together information on farm subsidies, farm equipment, crop insurance and weather conditions. It also provides information on available stock of seeds and fertilizers in local government and private stores.
c) Major floriculture zones
Hosur, Chennai, Madurai, Trichy, Coimbatore, Kanyakumari and Hill area zones are some of the major floriculture zones,
d) Azospirilium
1. Azospirillum has the ability to use atmospheric nitrogen and transport. This nutrient to the crop plants. It, is inoculated on maize, barley, oats and sorgham crops.
2. It increases productivity of cereals by 5-20% of millets by 30% and fodder by over 50%.

Typhoid causative agent: Salmonella typhi
Mode of entry of the pathogen:
Through food and water contaminated with faeces of infected person and through houseflies.
Diagnostic symptoms:
High fever, weakness, abdominal pain, headache, loss of appetite, rashes on chest and upper abdomen.
Organ affected in severe cases:
Human Digestive system gets affected and the blood can carry the bacteria to other organs including the lungs, liver, gall bladder and kidneys.

Xerophytes:
Plants that grow in dry habitat are called xerophytes. They develop special structured and physiological characteristics to meet the following conditions.
i) To absorb as much water as they can get from the surroundings.
ii) To retain water in their organs for very long time.
iii) To reduce transpiration rate.
iv) To reduce consumption of water.
Adaptations of xerophytes:
1. They have well developed roots, Roots grow very deep and reach the layer where water in available as in allotropic.
2. They store water in succulent water storing parenchymatous tissues. eg: Opuntia, Aloe vera.
3. They have small sized leaves with waxy coating ego Acacia. In some plants leaves are modified into spines eg: Opuntia.
4. Some of the xerophytes complete their life cycle within a very short period when sufficient moisture is available.

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. SONAR stands for Sound Navigation and Ranging.
2. It is a device that uses ultrasonic waves to measure the distance, direction and speed of underwater objects.
3. It consists of a transmitter and a detector and is installed at the bottom of the boats and ships.
4. The transmitter produces and transmits ultrasonic waves.
5. These waves travel through water and after striking the object on seabed, get reflected back and are sensed by a detector.
6. The detector converts the ultrasonic waves into electrical signals which are appropriately interpreted.
7. The distance of the object that reflected the sound wave can be calculated by knowing the speed of sound in water and the time interval between transmission and reception of the ultrasound.
8. Let the time interval between transmission and reception of ultrasound signals be 't' and the speed of sound through sea water be 2d/t = v. This method is called echo ranging.
9. SONAR technique is used to determine the depth of the sea and to locate underwater hills, valleys, submarine icebergs etc.,

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.

1. An object will sink or float in a liquid is determined by the density of the object compared to the density of the liquid .
2. If the density of a substance is less than the density of the liquid it will float. For example, a piece of wood which is less dense than water will float on it.
3. Any substance having more density than water for example a stone, will sink into water.

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

b) Both assertion and reason are true but reason is not the correct explanation of assertion.

a) Pisiculture
Pisiculture or Fish culture is the process of breeding and rearing of Economically important fishes under controlled conditions in ponds, reservoirs, lakes, rivers and paddy fields.
b) Apiculture
Apiculture is the rearing of honey bee for honey. Honey bee is domesticated by farmers to produce honey.
c) Vermiculture
The artificial rearing or cultivation of earthworms for the production of vermicompost.
d) Mariculture
Culture of fishes and other aquatic organism in marine water near the sea coast.
e} Floriculture
Production of ornamental plants.
f} Compost
A decomposed organic matter which is rich in nutrients. It is a soil conditioner, fertilizer, natural pesticide.
g} Pomiculture
Growing (or) cultivation of fruits.
h} Pinning
During Mushroom cultivation Mycelium starts to form little bud, which will develop into mushroom. Those little white buds are called pins.

The horizontal velocity that has to be imparted to a satellite at the determined height, so that it makes a circular orbit around the planet is called orbital velocity.

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

Forensic chemistry applies scientific principles, techniques and methods to investigate a crime.

Four valence electrons termed as tetravalency.

Density of water = 1g cm^-3
Density in SI unit = ?
1g = 1000 kg/m³
1 cm³ = 1 x 10^-6m³
1 g / cm3 = \(= \frac{10^-3}{10^-6}\)= 1000 kg/m³
In SI unit density of water is 1000 kg/m³.

The pH of a crop land is 5. So it is acidic in nature. So we use ammonium nitrate and calcium phosphate, urea. They are basic in nature.