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In the figure, given two triangles are congruent. So, the corresponding parts are:

 A ↔ O, R ↔ W, T ↔ N. We can write,  Δ  RAT ≅  Δ  WON [By SAS congruence rule]

Blended fabrics- combination of two or more fabrics. Example- Terylene

(a) Large number of terms to identify synthetics.

(b) Consumer being mislead by shopkeeper.

import numpy as np

import pandas as pd

df1 = pd.DataFrame({'mark1':[30,40,15,40],

'mark2':[20,45,30,70]});

df2 = pd.DataFrame({'mark1':[10,20,20,50],

'mark2':[15,25,30,30]});

print(df1)

print(df2)

(i)  print(df1.add(df2))

(ii)  print(df1.subtract(df2))

(iii)  df1.rename(columns={'mark1':'marks1'}, inplace=True) print(df1)

(iv)  df1.rename(index = {0: "zero", 1:"one"}, inplace = True) print(df1) 

(b) Analogous structures are: 

* Wings of butterfly and birds: Both are used for flying but have different internal structures.

* Tubers of sweet potato and potato: Both are used   for food storage, but have different structure and origin.

Differences between analogous and homologous structures :

(a) Analogous : Anatomically not similar though perform similar functions / are a result of convergent evolution.

Homologus : Anatomically similar (but perform different functions) / are a result of divergent evolution.

Bacteria : Bacillus thuringiensis 

Fungus : Trichoderma

Insect : Ladybird / Dragonfly / Moth or any other correct example

Stirring type

• Mixing of reactor contents evenly (with agitator system or a stirrer)

• Facilitates oxygen availability

• Temperature / pH / foam control // under optimum conditions

(i) Reduces dependence on toxic chemicals.

(ii) Protects our ecosystem or environment.

(iii) Protects and conserves non-target organisms / they are species - specific.

(iv) These chemicals being non-biodegradable may pollute the environment permanently.

(v) These chemicals being non-biodegradable may cause biomagnification.

(a) It recognises a specific sequence of base pairs pallindromes, and cuts the DNA strand at a specific site

eg. EcoRI / Hind II or any other correct example

(b) Act as vectors / cloning of desired alien gene / foreign gene

eg. pBR322 / plasmid of Salmonella / plasmid of Agrobacterium / Ti Plasmid / Tumour inducing Plasmid 

Out-breeding is the breeding of the unrelated animals, which may be between individuals of the same breed but having no common ancestors fro 4-6 generations (out-crossing) or between different breeds (cross-breeding) or different species (inter-specific hybridisation).

Out-crossing: It is the mating of animals within the same breed. Thus, they have no common ancestors on either side of their pedigree up to 4-6 generations. The offspring of such a mating is known as out-cross. It is the best method for animals having low productivity in milk production, growth rate in beef cattle, etc. It helps to overcome inbreeding depression.

Cross-breeding: In this type of breeding, the mating occurs between different breeds of same species, thereby producing a hybrid. 

Here, the superior males of one breed are mated with superior females of another breed. The desirable qualities of two different breeds are combined. For example, Hisardale (sheep) is a new breed developed in Punjab by crossing Bikaneri ewes and Marino rams.

(a) The speaker is Mr. Jenkins, the publisher of a magazine. 

(b) Mr. Jenkins is asking the narrator to write a ghost story for his magazine. 

(c) supernatural

(a) both of them defy age and their critics 

(b) he just tries to live and enjoy his roles 

(c) he seems to have reidentified himself

(a) life was rather tough and he desparately needed a job. 

(b) that they had a vacancy in their office for the post of an Accounts Officer 

(c) said that he had five years experience in a reputed firm as an Accounts Officer

(a) he has another world record to his credit 

(b) whether they can hope for a 400 plus innings in a test match. 

(c) he will not disappoint his countrymen

Broad spectrum antibiotics:

Antibiotics which kill or inhibit a wide range of Gram-positive and Gramnegative bacteria.

e.g. Chloramphenicol. 

Analgesics:

Reduce or abolish pain without causing impairement of consciousness, mental confusion, incoordination or paralysis or some other disturbances of nervous system.

e.g. Aspirin / paracetamol etc. 

1. Disproportionation reaction takes place in which chlorine from its zero oxidation state in Cl2 gets disproportionate into NaC103 (oxidised form) and NaCl (reduced form). The reaction is
   3Cl₂ + 6 NaOH (Hot and cone.) → NaClO₃ + 5 NaCl + 3 H₂O
2. XeF₆ + SbF₅ → [XeF₅]⁺[SbF₆]^–
   XeF₆ loses its F^– ion which is taken by SbF₅ to form cationic and anionic species. Due to ionic species, this mixture will conduct electricity in molten state.

(i)

(ii)

(a) Moist sulphur dioxide behaves as a reducing agent, reduces MnO₄^- to Mn²⁺ . X – X’ bond in interhalogens is weaker than X - X bond in halogensexcept F^-

(b) F bond.

(c)  Due to the ease with which it liberates atoms of nascent oxygen.

Sexual reproduction occurs in mosquito, and the asexual reproduction takes place in human body.

Population size increases with the increase in ‘r’ and it decreases with the decrease of ‘r’.

(i) Sporozoite 

(ii) Gametocytes

Pollen tube carries two male gametes. 

Pollen tube, after reaching the ovary, enters the ovule through the micropyle and then enters one of the synergids through the filiform apparatus which guides the entry of pollen tube.

(i) Compounds of carbon and hydrogen are called hydrocarbons. e.g. methane, ethane, etc. 

(ii) Saturated hydrocarbons contain carbon–carbon single bonds, e.g., methane, ethane. Unsaturated hydrocarbons contain atleast one carbon– carbon double or triple bond, e.g., ethene, ethyne. 

(iii) Functional group is an atom or group of atoms joined in a specific manner which is responsible for the characteristics properties of the organic compounds, e.g., OH, —CHO.

The square of the absolute value of wave function |ψ²| denotes the probability of finding the electron in an orbital.

(a) Correct statement 

(b) When temperature is increased at equilibrium, endothermic reaction proceeds in forward direction and an exothermic reaction proceeds in backward direction. Pressure has no effect on equilibrium when equal number of gaseous molecules of reactants and products are present and increase of pressure shifts the equilibrium in the direction with lesser number of gaseous molecules. 

(c) The solution which resists change in pH on addition of small amount of acid or alkali.

Detailed Answer : 

(a) If a chemical reaction at equilibrium is subjected to small changes in P, T or concentration, the equilibrium shifts in a direction so to undo the effect of the change. 

(b) Effect of temperature - Increase of Temperature 

(i) For exothermic reactions, equilibrium shifts in backward direction. 

(ii) For endothermic reactions, equilibrium shifts in forward direction. 

Effect of Pressure - Increase of pressure shifts the equilibrium in the direction with lesser number of gaseous molecules and no effect of pressure in case of equal number of molecules of reactants and products.

(c) Example of Buffer Solution : CH₃COOH + CH₃COONa (Acidic buffer solution) NH₄OH + NH₄Cl (Basic buffer solution)

(a) Acid is a substance which accepts pair of electrons.  Base is a substance which denotes pair of electrons.

(b) Correct Statement, Strength or polarity of H — A bond 

(c) 10–14

Detailed Answer :

(b) The suppression of ionisation of an electrolyte by adding an electrolyte containing a common ion. The strength of an acid depends on the polarity of H-A bond. More polarity leads to more acidity

i) Metal, Basic
ii) X(NO₃)_2, XSO₄
These compounds are ionic/ electrovalent 

Expected points 

1. Imperialistic and social respect 

2. Equality 

3. Women empowerment 

4. Freedom of work

(i) Coconut and Paan.

(ii) (a) The nut resembles a man’s head.

(b) The fibre on the fruit which looks like human hair, is used to make cords and cables for shipping vessels.

(iii) (a) Ibn Battuta compares coconuts with human head as the resembles to human head.

(b) It has two eyes and a mouth and its inner part is grown, which look like the brain.

(c) The fiber attached to it look like hair.

(i) Historians should observe the language in which the book has been written. They should examine if the book has been written in Pali, Prakrit or Tamil which were usually spoken by the people. Further they see whether the book was been written in Sanskrit which was used by the specific section of the society. 

(ii) They paid their attention to the kind of text. They tried to analyse if the text contained mantras which could be read by the people. 

(iii) Historians wanted more to know the authors whose ideas and thoughts gave the text a concrete shape.

(i) The term ‘shadow lines’ refers to the hastily constructed frontiers separating India and Pakistan. 

(ii) The boundaries between the two new states were not officially known until.

(i) (a) By equal right to property and access to education to hold jobs to empower them economically. 

(b) Equal opportunities for jobs and equal pay. 

(ii) (a) Equality and cooperation between genders.

(b) Women being treated at par with men. 

(iii) (a) Hansa Mehta did not demand reserved seats and separate electorates for women because she realised not only would it be divisive in nature but create resentment. 

(b) She did not went privileges for women but to empower them by their own efforts.

(c) The saying goes not to give them fish but should teach them to catch the fish so that they could become self-sufficient and not dependent.

(i) The villages headman was known as the Muqaddam. Some sources suggest that he was appointed by consenses of the village elders and the choice had to be ratified by the zamindar. 

(ii) The main duty of the village headman was to supervise the preparation of village accounts; with the help of the Patwari.

(i) Alexander Cunnigham, the first Director General of the Archaeological Survey of India is often called the father of Indian Archaeology. 

(ii) Alexander noted that the amount of brick taken from the ancient site was enough to lay bricks for about 100 miles of railway line between Lahore and Multan.

                  Be Helpful to Others 

Once upon a time there was a young girl who wished to see the world. She wanted to observe new things. She told her mother about her wish. Her mother promised that they would go to a hill station. Next Sunday, they set out on their journey. On their way, they crossed many areas of terrace-farming, rivers and enjoyed the natural beauty. The young girl, whose name was Neha, was very excited. She was watching everything out of the window of her car with great curiosity. Suddenly, the car stopped with a jerk. The driver got out of the car to check why a crowd had gathered there. After some time, he came back and told them that due to a landslide, they could not go any further. Neha became sad. All her excitement vanished. She looked out and noticed that there was a great hustle and bustle outside. People were running helter-skelter. Soon there was a long queue of vehicles. People were trying to contact the authorities or their relatives for help on phone. Babies were crying for food and water. Then she noticed that the people who had eatables with them were sharing them with others. They were helping each other. She was amazed at this. She attracted her mother’s attention towards her who told her that it is a good thing to help each other and that one must do it. Neha checked her bag and found some chocolates which she had carried with her to eat during the journey. She came out of the car and distributed them to the little children. The children were very happy. Soon it started getting colder. But by then, authorities had started clearing the way for the vehicles to pass. After an hour of work, the road was cleared and the vehicles started moving at a snail’s pace. Neha was happy. Today’s experience had made her observe that helping others is the best way to be happy.

The Covid-19 pandemic has uncovered the foremost struggles of the twenty first century: social-economic inequality, global value chains, national security, and the environmental crisis. None of these seems novel, as many staged fiction dystopias have ...

The COVID-19 pandemic has abruptly disrupted progress toward many of the Sustainable Development Goals (SDG). Accordingly, the UN has underscored the need to design short-term responses to halt and reverse the adverse effects of the current COVID-19 ...

Sustainable development is the idea that human societies must live and meet their needs without compromising the ability of future generations to meet their own needs. Specifically, sustainable development is a way of organizing society so that it can exist in the long term.

(i) The hot and the cold deserts 

(ii) High rainfall zones near the equator.

When we place few crystals of potassium permanganate in a beaker containing water, we get two distinct layers colourless water at the top and pink colour at the bottom. After few minutes, pink colour spreads and whole solution turns pink due to diffusion. Since potassium permanganate is a solid substance, it does not possess so much space. Water molecules due to liquid state, collide with solid particles and intermix due to sufficient space between molecules.

Long term perspectives of natural resources are:

1. It can be used further for next generation.

2. It will reduce pollution.

3. No need to find alternatives of them.

Metallic substances conduct electricity through electrons while ionic substances conduct electricity in molten state or in solution through ions.

Vertical columns of the periodic table are known as groups. 

(i) The number of valence electrons remains constant when we move down the group. 

(ii) The number of occupied shells increases down the group. 

(iii) The size of atom increases down the group. 

(iv) The metallic character of elements increases down the group. 

(v) The effective nuclear charge decreases down the group.

(i) Aim of classifications : Systematic study of the known elements. 

(ii) Basic property : Atomic number. 

(iii) Properties of the elements are a periodic function of their atomic numbers. 

(iv) Metals on the left. 

(v) Non-metals on the right. 

(vi) Metalloids at the border of metals and beginning of non-metals. 

A metal is obtained from its carbonate ore by converting it into its oxide by the process of Calcination. In Calcination, the ore is heated to a high temperature in the absence of air.

ZnCO₃(s) +heat→ ZnO(s)+CO₂(g)

The metal oxides obtained by calcination are converted into the free metal by using reducing agents like carbon, aluminum which depend upon the reactivity of the metal.

ZnO+C→Zn+CO.

Impure Zn obtained is refined by the electrolysis process.

Properties of elements are a periodic function of their atomic number.

It is considered as a substitution reaction because the hydrogen atoms of methane (CH₄) are replaced by chlorine atoms one by one.

Henry Moseley.