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H₂S, due to low bond dissociation enthalpy of H–S bond.

(i) Acetic acid will remain colourless in phenolphthalein.

(ii) Acetic acid will dissolve in distilled water forming a clear solution.

(iii) Universal indicator gives orange colour with acetic acid.

(iv) Sodium hydrogen carbonate will give brisk effervescence due to the formation of CO₂ gas.

The correct answer is

(B)

The correct answer is

(A)

(c) Real, inverted, diminished and in blue shade 

The correct answer is

(D)

(i) Maximum level of bio magnification occurs here because of progressive accumulation. 

(ii) We get very small amount of energy as only 10 %, of the previous energy gets transferred at each trophic level.

Scientific soil and water conservation is called watershed management. 

Advantages: 

(i) Increases production and income of watershed community. 

(ii) Mitigates droughts and floods. 

(iii) Increases the life of downstream dams reservoirs.

The changes in the daily needs of iron and calcium for pregnant women are as follows 

1. 38 mg of iron, compared to 30 mg for a normal woman. 

2. 1000 mg of calcium, compared to 400 mg for a normal woman.

Indicators by which I will know the dress has not been cut along the selvedge are as follows 

• The dress will feel uncomfortable to the person wearing it.
• The dress would not last very long.

Correct Option (b) Par

Correct Option (c) Market value

Correct Option (b) seven

Correct Option (a) Equity

Match the pairs 

 (a) 3,

(b) 8,

(c) 1,

(d) 10,

(e) 2

Distinguish between the Dematerialisation and Rematerialisation.

Transfer of Shares and Transmission of Shares

Primary Market and Secondary Market.

Shares and Debentures

Examples of consumers facing problems in quality of products are as follows

• There is adulteration in the products.
• The products are below the prescribed standards of quality.
• The labels on the goods are either misleading or incomplete.
• The weights or measures are actually less than the ones mentioned on the label. 

Examples of consumers facing problems in prices of products are as follows

•  Shopkeepers charge higher prices than the Maximum Retail Price (MRP).
• They sell loose items without labels or packages and charge arbitrary prices for loose items.
• Poor quality goods are sold at the price of good quality popular brands.
• Prices are not fixed and prices between two shops also vary.

Factors which would influence Rehana’s selection of foods are as follows

• Energy Requirement Rehana’s husband’s energy requirement will depend upon whether he is a heavy, moderate or sedentary worker.
• Children’s Requirements Rehana’s children will require food according to their age. Food for infants, pre-school children, school going children or adolescents have to be planned according to their age group. ‘
•  Locally Available Foods As Rehana’s family is living in a coastal area, seafood and fish are cheaper and so will be a regular constituent of their meals.
•  Available Medium for Cooking They may use coconut oil for cooking, as it is abundantly available in coastal areas. 

Reasons for Rehana to plan the meals for her family are as follows  

• The family members should get the nutrients they require.
• The meals should give a feeling of satiety.
• The meals should have variety in food groups, colour, texture, taste, flavour etc so that the family members are interested in eating. 
• Rehana should save time, money and energy by planning the meals.

Interim dividend and Final dividend.

(1) Money Market 

(2) Bonus Shares

(3) Fixed Rate Bonds

(4) Depository Participant

(5) Dividend warrant

The reasons in support are: 

(i) Processes like metabolism, translation and splicing evolved around RNA. 

(ii) RNA is reactive and catalyses reactions. 

(iii) In some viruses, RNA is the hereditary material. 

(iv) RNA is unstable and can be easily mutated leading to evolution.

Correct option: (1) 0.5 mm and (+ 0.0015) cm

Explanation: 

We have L.C = Pitch/100

∴ Pitch = 0.0005 × 100 cm = 0.05 cm

 = 0.5 mm 

Total observed reading = (0.65 mm) + (43 × 0.0005) cm 

= 0.0865 cm 

Correct reading = Observed reading – (zero error)

∴ Zero error = (0.0865 – 0.0850) cm 

= + 0.0015 cm

Similarities between laboratory thermometers and clinical thermometer is that they both have mercury in them and are used for measuring temperature.

Differences Clinical thermometer is used to measure human body temperature whereas laboratory thermometer is used to measure temperature of other object which has higher temperature than human body temperature. 

• The temperature range of clinical thermometers is 35°C-42°C and that of laboratory thermometers is -10°C-110°C.
• The least count of both the thermometers is different.

(i) The direction of magnetic field produced around a current-carrying conductor is given by right hand thumb rule. If the conductor carrying current is held in the right hand in such a way that the thumb points in the direction of current, then direction of curl of fingers gives the direction of the magnetic field. 

(ii) The direction of force experienced by a straight conductor carrying current placed in a magnetic field, which is perpendicular to it is determined by Fleming’s left hand rule. Hold the thumb and first two fingers of the left hand at right angles to each other with the first finger pointing in the direction of the field and the second finger in the direction of the current, then the thumb points in the direction of the motion. 

(iii) The direction of current induced in a circuit by changing magnetic flux due to motion of a magnet is determined by Fleming’s right hand rule. If we stretch our right hand in such a way that the thumb, forefinger and central finger remain perpendicular to each other, so that the forefinger indicates the direction of the magnetic field and the thumb in the direction of motion of conductor; then the central finger indicates the direction of induced current.

Fuse is used for protecting appliances due to short-circuiting or overloading. The fuse is rated for a certain maximum current and blows off when a current more than the rated value flows through it. If a fuse is replaced by one with larger ratings, the appliances may get damaged while the protecting fuse does not burn off. This practice of using fuse of improper rating should always be avoided.

(i) Auxin diffuses to the other part which is away from the support. Part of the tendril in contact from the support does not grow rapidly. H 2 Part of the tendril away from the support grow rapidly and cause the tendril to grow around a support. 

(ii) Chemotropism—Movement in plant due to chemicals as stimulus. Example: Growth of pollen tubes towards ovules (or any other).

Fertilisation

• The process of fusion of a sperm (male gamete) with an ovum (female gamete) is called fertilisation.
• During coitus, semen is released by the penis into the vagina (insemination).
• The motile sperms swim rapidly, through the cervix, enter into the uterus and reach the ampullary–isthmic junction of the oviduct. 
• A sperm comes in contact with the zona pellucida layer of the ovum and induces changes in the membrane to block the entry of additional sperms. 
• The enzymes of the acrosome of sperm help to dissolve zona pellucida and plasma membrane of the ovum and sperm head is allowed to enter into the cytoplasm of the ovum, i.e., secondary oocyte.
• Ultimately, diploid zygote is produced by the fusion of a sperm and an ovum.

On its entry into the body, HIV attacks macrophages. 

Lifecycle of HIV 

• After getting into the body of a person, the virus enters into macrophages, where RNA replicates and forms viral DNA by the help of enzyme reverse transcriptase. 
• The viral DNA gets incorporated into the host cell’s DNA and directs the infected cells to produce viruses. 
• The macrophages continue to produce virus that enters the helper T-lymphocytes. 
• Thus, the number of helper T-lymphocytes progressively decreases in the body of the infected persons. 
• Thus, the person suffers from various pathogens like Mycobacterium, viruses and parasites like Toxoplasma.

Convergent evolution: When more than one adaptive radiation appeared to have occurred in an isolated geographical area and two or more groups of unrelated animals resemble each other for similar mode of life or habitat; it is called convergent evolution; eg., Australian marsupials, placental mammals. 

Divergent evolution: In some animals, the same structure developed along different directions due to adaptions to different needs. This is known as divergent solution; eg., forelimbs of whales, bats, cheetah and human, perform different functions as they have similar anatomical structure.

Animals like whales, bats, cheetah and humans share similarities in the pattern of bones of forelimbs. In these animals, the same structure is developed along different directions due to adaptions to different needs. This is divergent evolution. Whereas in convergent evolution, the different structures evolve for the same function and have similarity. An example is the eye of octopus and of mammals or flippers of penguins and dolphins.

(i) Events taking place at: 

(a) stage (1) — Follicular maturation 

(b) Transfer to surrogate mothers 

(ii) Due to this technology, high milk-yielding breeds of cows and high quality meat yielding bulls have been bred successfully to increase herd size in a short time.

The organism from where the thermostable DNA polymerase is isolated is Thermus aquaticus. It has wide role in genetic engineering as it is used in PCR because it can withstand high temperatures, which is applied to separate DNA strands. 

(i) Monoecious plant—Cucurbits  

(ii) Bearing pistillate flowers—Date palm

The process of mating more closely related animal within same breed is called inbreeding. The recessive alleles become homozygous and express themselves. These are then eliminated by selection.

The pyramid of biomass in sea is generally inverted because the biomass of fishes far exceeds that of phytoplankton and the number of big fishes eating the small fishes is also greater than the small ones. Also in pyramid of number, the number of insects feeding on a big tree is far greater than the tree. Now the number of small birds depending on the insects and the number of larger birds eating the smaller ones also increases in the order.

The cross between two individuals of different species of the same genus is called interspecific hybridisation. Saccharum officinarum × sacchaum barbari. Advantage is that a disease resistance variety high yielding variety can obtained.

(i) Slower decline in birth rate and sharper decline in death rate.

(ii) Improved health facilities and longer life span.

Two reasons for increase in population are: 

(i) A rapid decline in death rate, maternal mortality rate and infant mortality rate. 

(ii) Increase in number of people in reproducible age.

Two reasons for decline in population are: 

(i) Statutory raising of marriageable age of the female to 18 years and male to 21 years. 

(ii) Incentives given to couples with small families.

1. Separating funnel
2. Sublimation
3. Evaporation
4. Filtration
5. Centrifugation

1. Mollusca
2. Echinodermata
3. Porifera

The near point of an eye is known as least distance of distinct vision.

• It is defined as the minimum distance between the eye lens and the object to form a clear image.
• For young people the least distance of distinct vision is less and for old it is more.

When a solid is heated then there is increase in temperature which causes breakage in between strong intermolecular bonds of the atoms. As a result, the atoms move at a distance and start to collide.

Thus, there will be increase in the kinetic energy and there will be change in the state of matter.

For example, when ice is kept at room temperature then it starts to melt because of the surrounding heat. As a result, it changes into water.

H₂O(s) + heat → H₂O(l)

On further increasing the temperature, the liquid state will convert into gaseous state.

Similarly, when we increase pressure on a liquid substance or matter then the molecules start to come closer to each other. As a result, the liquid state will change into solid.

H₂O(l) + pressure → H₂O(s)

Also, when pressure is increased on a gas it will start to convert into liquid state.

Effects of Global Warming:

(i) Due to increase in CO₂ concentration, the rate of photosynthesis will increase especially in C₃ plants This is called CO₂ Fertilisation.

(ii) Rise in temperature due to global warming will raise sea level due to melting of glaciers and ice caps of polar regions which in turn will lead to submergence of coastal areas.

(iii) Rise in temperature is detrimental to crop productivity due to increase in respiration, growth of weeds, eruption of diseases and pests, especially in tropical and subtropical areas.

(iv) It will have adverse effect on weather, climate and atmosphere.

Four measures to control noise pollution are:

(i) Noise pollution control laws should be strictly enforced.

(ii) Green muffler or green belt vegetation should be planted along roads and rails for absorption of noise.

(iii) Loudspeakers and entertainment gadgets should not be used beyond the permissible limit/time.

(iv) All machines whether industrial or engines of motor vehicles should be designed to produce lesser noise, maintained properly and lubricated timely. 

Biological Oxygen Demand or BOD is the amount of dissolved oxygen required by the micro organisms in metabolizing the organic wastes present in water.

Significance of BOD in an Aquatic Ecosystem

BOD is directly proportional to the input of organic wastes.

It BOD is increased, the dissolved oxygen (DO) in the water is decreased. Higher amount of organic waste increases the rate of decomposition in the water. Oxygen is rapidly consumed by the microbes, there by causing a drop in the dissolved oxygen content in water. This effects the aquatic plants and animals in the water body.