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The correct answer is 1793 A.D.

Key Points

• Lord Charles Cornwallis was the Governor-General of Bengal when the Permanent Settlement was introduced in 1793.
• By the terms of the settlement, the rajas and taluqdars were recognised as zamindars and were asked to collect rent from the peasants and pay revenue to the Company.
• The amount to be paid was fixed permanently, that is, it was not to be increased ever in future.
• It was felt that this would ensure a regular flow of revenue into the Company’s coffers and at the same time encourage the zamindars to invest in improving the land.
• Since the revenue demand of the state would not be increased, the zamindar would benefit from increased production from the land.

The correct answer is option 2 i.e. AIDS.

Concept:

Angle opposite to the greater side is greater.

Calculation:

PQ = 4 - 0.270 = 3.730 cm

QR = 2 + 1.732 = 3.732 cm

PR = 1.35 + 2.381 = 3.731 cm

∴ Side QR is largest hence ∠P or ∠QPR has the maximum measure

The correct answer is Zn.

Key Points

• Only a few elements have been found to be absolutely essential for plant growth and metabolism.
• These elements are further divided into two broad categories based on their quantitative requirements:

(i) Macronutrients, and (ii) Micronutrients.

• Macronutrients are generally present in plant tissues in large amounts.
• The macronutrients include carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorous (P), sulphur (S), potassium (K), calcium (Ca) and magnesium (Mg).
• Of these, carbon, hydrogen and oxygen are mainly obtained from CO₂ and H₂O, while the others are absorbed from the soil as mineral nutrition.
• Micronutrients or trace elements are needed in very small amounts.
• These include iron, manganese (Mn), copper (Cu), molybdenum (Mo), zinc (Zn), boron (B), chlorine (Cl) and nickel (Ni).

Additional Information

• In addition to the 17 essential elements named above, there are some beneficial elements such as sodium (Na), silicon (Si), cobalt (Co) and selenium (Se). They are required by higher plants

Given:

HCF of 3 numbers = 6

LCM = 630

Two numbers are 18 and 42

Concept:

HCF is the highest common factor of some given numbers. When we divide the numbers by their HCF, the quotients will be prime to each other.

LCM = HCF × Product of the quotients after dividing the numbers by the HCF

Calculation:

Let, the numbers be 6x, 6y and 6z where x, y and z are prime to each other

Also let, two numbers are 6x and 6y 

⇒ 6x = 18

⇒ x = 3

and 6y = 42

⇒ y = 7

LCM of the numbers = HCF × yxz

⇒ 630 = 6 × 3 × 7 × z

⇒ z = 5

The 3^rd number is 6z = 6 × 5 = 30

∴ The third number will be 30.

The formula LCM × HCF = Product of the numbers is only applicable in the case of two numbers.

When it comes to three or more numbers it will not work.

For example:

HCF of 2, 4 and 6 is 2 and LCM = 12

Now LCM × HCF = 12 × 2 = 24

But, the product of the numbers is 2 × 4 × 6 = 48

The correct answer is Radon.

1. Radioactivity is a nuclear phenomenon in which an unstable nucleus undergoes decay and is referred to as radioactive decay.
2. Three types of radioactive decay occur in nature :

(i) α-decay (ii) β-decay (iii) γ-decay 3. Noble Gases

1. There are six elements in Group 18 of the Periodic Table - Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr) , Xenon (Xe) and Radon (Rn) which were earlier termed as inert gases or rare gases.
2. Both of these terms are now no longer used as they are not so rare and not completely inactive. They do show some chemical reactivity in the form of some xenon and krypton compounds and hence are termed as noble gases.
3. Occurrence
4. All the noble gases except Radon occur in the atmosphere. Xenon and radon are the rarest elements of the group.
5. Radon is a radioactive element. Radon (²²²Rn) is a decay product of Radium (²²⁶Ra) and is obtained by pumping off the gas from radium chloride solutions.
6. They are the minor constituent of the air, the atmospheric abundance being ~ 1% by volume of which argon is the major constituent. Ne, Ar, Xe and Kr are obtained by fractional distillation of liquid air.
7. Helium and sometimes neon is found in minerals of radioactive origin e.g., pitchblende, monazite, cleveite. The main commercial source of helium is natural gas to an extent of 2-7%.
8. They have closed valence shell electronic configuration due to which they have the least tendency to react.
9. The best-characterised compounds are those of xenon with fluorine and oxygen only under certain conditions and only with highly electronegative fluorine and oxygen.
10. Uses: These gases have several uses. Argon is used to provide an inert atmosphere, helium is used in filling balloons for meteorological observations, neon is used in discharge tubes and fluorescent bulbs.

The correct answer is Nucleus.

The correct answer is option 4 i.e. Black.

Key Points

The correct answer is Dinabandhu Mitra.

• Nil Darpan (The Indigo Planting Mirror) is a Bangla play by Dinabandhu Mitra in 1858–59 and published in Dhaka in 1860, under a pseudonym.
• It depicted the Indigo Revolt of February–March 1859 in Bengal, when farmers refused to sow indigo in their fields to protest against exploitative farming under the British Raj.
• It was also essential to the development of theatre in Bengal where the first play ever commercially staged was "Nildarpan".
• Michael Madhusudan Dutt translated the play into English immediately after it was published.
• Bankim Chandra Chattopadhyay compared Nil Darpan to Uncle Tom's Cabin for its role in arousing people's awareness of the evils of indigo plantations.

Additional Information

The correct answer is Potato.

Modifications of Root

1. For storage of food

• Roots are modified in some plants for storing reserve food materials.
• These modified roots usually are swollen and assume different forms such as spindle-shaped, e.g., radish; top-shaped, e.g., beet, turnip; cone-like, e.g., carrot; indefinite shape, e.g., sweet potatoes.
• Dahlia, Asparagus, Portulaca are some other examples of plants with modified roots for food storage.

2. Nodulated roots

• The roots of pea and other leguminous plants have numerous swollen nodules on fine branches of roots.
• These nodules are formed due to the symbiotic association of Rhizobium (bacterium) that live inside the root cortical cells of the roots.
• They fix nitrogen and an active nodule is pink in colour.

3. For mechanical support

• Roots are modified to provide mechanical support as seen in a banyan tree which has roots growing vertically/obliquely downwards (prop roots); sugarcane/maize in which roots arise from the nodes in the cluster at the base of the stem (stilt roots) and betel/black pepper in which nodes and internodes bear roots which help in climbing.

4. For gaseous exchange

• Pneumatophores or breathing roots are found in plants growing in mangroves or swamps with saline water for exchange of gases.
• They are erect peg-like structures with numerous pores through which air circulates e.g., Rhizophora mangle.
• Modifications of Stem

1. For storage of food

• Stems get modified into underground structures for storage of food as seen in potato (tuber), ginger (rhizome), garlic (bulb), yam (corm).
• Presence of an eye (node) in potato, distinct nodes with internodes and scaly leaves in ginger/yam, a cluster of roots at the base of the reduced stem in garlic/ onion, all indicate that these underground plant parts are modified stem.

2. For vegetative propagation

• Plants besides reproducing sexually also propagate through vegetative parts.
• For this purpose, stems may be modified into a runner (Cyanodon dactylon, Oxalis). Runners are slender prostrate branches arising from axillary buds;
• stolon (e.g., mint, strawberry) which is a slender lateral branch arising from the base of the stem grows upward and then down to develop new daughter plants;
• offset having a single long horizontal internode growing up to some distance and producing a tuft of leaves above and a cluster of roots below at the apex (Eichornia, Pistia) and
• sucker, which arises from the underground part of the stem, grow obliquely and gives rise to a new shoot. (Chrysanthemum, Banana, Pineapple).

3. For protection

• Some modified stem provides protection as thorns which are hard, pointed structures each representing a branch that arises from the axil of a leaf.
• Thorns are found in plants like Duranta, Pomegranate, Acacia, Ber, Prosopis, Bougainvillea, Citrus, etc.

4. For support

• Tendrils are modifications of the stem to provide support to plants, e.g., Vitis, passionflower, Bignonia etc.

5. For photosynthesis

• Stems are also modified into Phylloclade, to facilitate photosynthesis.
• Phylloclades are flattened/cylindrical stem or branches of unlimited growth (Cactus).