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A specialised structure − mesosome is formed by the extension of plasma membrane into the cell. Mesosomes help in cell wall formation, DNA replication and distribution to daughter cells, respiration, secretion process, to increase surface area of plasma-membrane and enzymatic content.

Bacterial cells may be motile or non-motile. Motile bacterias have flagella composed of three parts − filament, hook and basal body. Pili and fimbriae are surface structures which do not play any role in motality. These structures help the bacteria to attach with rocks and the host tissues.

Answer is (A) Transition element

Correct Answer is: (A) Transition elements 

The position of d-block elements is in between the s-block and p-block elements in the periodic table. These d-block elements are called transition elements because they exhibit transitional behaviour between s-block and p-block elements.

Answer is (A) Transition elements

Applications of beats :

(1) Listening for beats – or rather, their absence-is the usual method of tuning musical instruments and in the determination of the frequency of a musical note.

(2) Ultrasonic vocal sounds made by bats and dolphins may be detected by superimposing a sound of different frequency to produce audible beats.

(3) In music, beats are used to produce a low frequency sound (a grave tone). Two notes whose difference in frequency is equal to the desired low frequency are used for this purpose. When two notes are nearly in tune, the beats are slow. But as the beat frequency increases to 20 Hz or more, the beats may ultimately merge into a continuous tone known as a difference tone.

(4) (i) Speed of a moving object can be determined using a Doppler RADAR. Radio waves from the RADAR are reflected off a moving object, such as an aeroplane. The superposition of the incident and reflected waves produces beats. The frequency of beats helps to determine the speed of the aeroplane.

The same principle is used in speed guns used by traffic police to determine the speed of cars on a highway.

(ii) In medicine, a Doppler ultrasound test (sonography) uses reflected sound waves to evaluate blood flow through the major arteries and veins of the arms, legs and neck. It can show blocked or reduced blood flow because of narrowing of the major arteries. Duplex (or 2D) Doppler, Colour Doppler and Power Doppler are different techniques of the same test.

Notes: Some other applications of beats are as follows :

1. Detection of toxic gases inside mines, especially collieries : Air from inside a mine and pure air are blown through two separate identical organ pipes. If beats are heard it would indicate that the composition of air inside the mines is different from that outside. This can serve as an early warning system.

2. In music, consonance and dissonance depend upon the beats produced when two notes are sounded simultaneously. A beat frequency between 10 Hz and 50 Hz (between the fundamental notes being played as well as any of their overtones) is unpleasant and results in dissonance.

3. Superheterodyne reception of radio waves in most radio, television and radar receivers : A low-frequency signal produced in the receiver is beat against an incoming high-frequency radio signal to produce an intermediate (beat) frequency (IF). This IF signal retains the information of the incoming signal. The receiver can be tuned to different broadcast frequencies by adjusting the frequency of the lowfrequency signal. The IF signal though can be kept the same in every case and can therefore be amplified with higher gain.]

Beat period = \(\frac1{beat \,frequency}\) = \(\frac1{10 Hz}\) = 0.1 s

Hence, the time interval will be 0.1 s in case (i) and 0.05 s in case (ii).

Answer is (B) Phosphorous

A periodic variation in loudness (or intensity) when two sound notes of slightly different frequencies are sounded at the same time is called beats.

If two notes of slightly different frequencies n₁ and n₂ are played simultaneously, the resulting

note from their interference has a frequency of (n₁ + n₂)/2. However, the amplitude of this resulting note varies from the sum to the difference of the amplitudes of the two notes n₁ and n₂ . An intensity maximum and an intensity minimum are respectively called waxing and waning. Thus, the resulting note will be heard as one of periodic loud (waxing) and faint (waning) sound. One waxing and one waning form one beat. Formation of beats is an example of interference in time.

The time interval between successive maxima or minima of sound at a given place is called the period of beats. 

The number of beats produced per unit time is called the beat frequency.

Correct Answer is: (A) Alkali metal 

The Group 1 elements in the periodic table are known as the alkali metals. They include lithium, sodium and potassium, which all react vigorously with water to produce an alkaline solution

Correct Answer is: (B) Phosphorous 

Group 15 elements include nitrogen, phosphorus, arsenic, antimony and bismuth. Nitrogen is the real constituent of the air and records for 78% of it by volume.

Answer is (B) Cu₂S and FeS

Correct Answer is: (B) Cu₂S and FeS 

Copper matte mainly contains Cu₂S and FeS. When a hot air blast is blown through molten matte taken in a silica lined converter, FeS is oxidised to FeO.

Consists of cisternae stacked parallel to each other. Two faces of the organelle are convex cis or forming face and concave trans or maturing face. 

Functions : Performs packaging of materials, to be delivered either to the intra-cellar targets or secreted outside the cell. Important site of formation of glycoproteins and glycolipids.

Demand refers to the quantity of a good, the consumer is willing to buy at a given price during a period of time.

(i) Own price of the good

(ii) Income of the buyers

(iii) Prices of related goods

(iv) Tastes and preferences of buyers.

(v) Number of consumers

(vi) Distribution of income.

Nutrient elements required in minute quantities to the plants are called micro nutrients.

Water that is fit for drinking is termed as potable water.

(c) Huntington’s chorea

Infrared radiations.

A mixture of smoke and fog is called smog.

When lakhs of trees are planted in July every year, it is termed as Van Mahotsav.

The small colonies of Sahariya tribe are called Sahartana and villages are called Saharol.

The community agriculture done by Garasiyas is called as “Hari Bhawari”.

The Sansi tribe lives in Bharatpur and Alwar districts in Rajasthan.

By the Government of India Act, 1919.

People of this tribe are expert in making catechu from the tree of Khair, so they are called Kathodi.

The Kathodi tribe of Rajasthan lives in Kotra, Jhadol and Sarada Panchayat areas in Udaipur.

The head of Panchayat of Damor community is called Mukhi.

Among Garasiyas, Caste Panchayats are very important. Caste Panchayats are held at the village and Bhakhar level. Caste Panchayat may punish any one physically or financially. The head of the Panchayat is called Sahalot.

The total number of members in the Chamber of Princes was 121.

In ancient time, there were two marriage systems Prevalent in Meena, tribe:

1. Brahma Vivah (arranged marriage). 

2. Gandharva Vivah (Love marriage).

The fairs related to Meena tribe are held in Mahavirji, Ganeshji (Sawai Madhopur) and in the temple of Jeenmata of Revasa in Sikar.

Sahariya is the most backward tribe in Rajasthan. So Government of India has included it in the primitive tribes of India. The houses in which people of Sahariya live are called Tapari and Topa. The small colonies of this tribes are known as Saharana and village as Saharol.

1. Residing Area: 98 per cent of Sahariya tribal people live in Kishanganj and Shahbad Tehsils in the district of Baran. 

2. Social Life: Nuclear families are seen in Sahariyas. They have polygamy system. The birth of a girl is considered fortunate. They consider Rishi Valmiki as their penates. 

3. Economic System: The main bases of their economy are forest – products and shifting agriculture. Literacy percentage in Sahariyas is very low.

The headquarters of the ‘Chamber of Princes’ council’ established on February 9, 1921 was in Delhi.

• Army 
• Railways.

(d) All these

(c) By Government of India Act, 1919

(d) By Government of India Act, 1919

In the Montague – Chelmsford report.

The male reproductive system in human beings consists of testes which produce sperms, vas deferens, seminal vesicles, prostrate gland, urethra and penis. 

The female reproductive system consists of a pair of ovaries, fallopian tube, uterus and vagina.

By the Government of India Act, 1919.

Albuminous seed: Seeds having the copious amount of endosperm. e.g., Wheat

Ex-albuminous seed: Seeds in which endosperm is used up. e.g., Grass

A maximum of 60 members.

The Viceroy had this right.

In diarchy system, provincial subjects were divided into :

• Transferred subjects. 
• Reserved subjects.

(a) Soak a few seeds of Bengal gram (chana) and keep them overnight. 

(b) Drain the excess water and cover the seeds with a wet cloth and leave them for a day. Make sure that the seeds do not become dry. 

(c) Cut open the seeds carefully and observe the different parts. 

(d) Compare your observations with the figure above that shows the germination of gram seed and see if you can identify all the parts.

(i) Take a petri dish. place damp cotton on it.

(ii) Put the dicot seeds on the petri dish. Allow it to germinate.

(iii) Place the germinated seed on the watch glass.

(iv) Open the two cotyledons with a forceps and needle.

(v) Observe the structure of seed.

(iv) Also, observe the embryonal axis with a magnifying glass and label its parts.

Puberty is the age at which the gametes start forming in the male and female human beings. At this age boys and girls become sexually mature.

A diarchy is a form of government characterized by co-rule, with two people ruling a polity together either lawfully or by collusion and force.

The important post-fertilization changes in flower are :

(i) Sepals, petals, stigma, style and stamen degenerate.

(ii) The fertilised egg develops into embryo.

(iii) The ovary ripens into fruit

(iv) The ovules ripens in-to seeds.

(v) The integument of ovule changes into seed coat and funicle changes into stalk of the seed.

These were :

• Legislative Assembly 
• Council of State.