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• The Greek kings minted characteristic coins.  
• On one side, the coin had a picture of the king who had minted the coin and on the other side, a picture of a Greek God. 
• The name of the king was also written on the coin. 
• Alexander’s coins were of the same type.

Correct option is: (b) influenced

Correct option is: (a) historians

1. Music was in Mohan’s blood because he was born into a family of musicians and he grew up with musicians.

2. Mohan was initially trained in vocal music.

3. Mohan played the violin and the sitar.

4. Mohan played the sitar for three years.

Largest component of bio-gas is Methane.

A. in summer

Father Brown, all through, tried to show as if he were a fool and never understood anything. So that Flambeau would never suspect him to be detective. The way he left the clues by changing salt and sugar, by splashing soup on the wall, by breaking the window, by increasing amount in the bill. This all shows that he was very intelligent.

Even at the end, the famous detective Valentin admits that Father Brown, was ‘master’ and he along with Flambeau would bow down to him. salt and sugar, by splashing soup on the wall, by breaking the window, by Increasing amount in the bill.

This all shows that he was very intelligent. Even at the end, the famous detective Valentin admits that Father Brown, was ‘master’ and he along with Flambeau would bow down to him.

Tehri Dam at river Ganga 

Sardar Sarovar Dam at river Narmada

(c) Both a and b

Normally pregnancy lasts for 280 day

1. The first menstrual flow begins at puberty and is termed menarche. 

2. It is the beginning of adolescence, during which mental and emotional maturation occurs and physical growth becomes pronounced.

The advantages of harnessing wind energy are :

(i) It is an environment-friendly and efficient source of renewable energy.

(ii) It requires no recurring expenses for the production of electricity.

(iii) It does not cause any pollution.

(i) Spurred concern about the environmental consequences of locating such a large dam in the fragile ecosystem of Himalayan foothills.

(ii) It is located in the central himalayan seismic gap, a zone of earthquake.

(iii) Dam break would submerge numerous iron fillings downstream.

(b) sebaceous

1. True.

2. False

3. True

4. False 

Correct statement: Making use of disposable napkins or tampons may reduce the chances of infections.

5. True

1. After ovulation, the ovum reaches the fallopian tube and fertilization takes place.

2. The fertilized egg undergoes development and it is implanted in the uterus.

3. The corpus luteum continues to grow and produces large amount of progesterone. 

4. This results in pregnancy. Normally, it lasts for 280 days, at the end of which parturition (child birth) takes place.

The basic characteristics of a good source of energy are as follows: 

1. The source of energy should be sustainable and renewable. 

2. It should not cause any kind of environmental pollution. 

3. It should produce a great amount of energy per unit mass or volume. 

4. It should not cause any kind of harm to people and should not be risky to the health of people handling it. 

5. The source of energy should be easily available and should have the capacity 

6. Energy and Good Fuel

We could then say that a good source of energy would be one.

1. Which would do a large amount of work per unit volume or mass.

2. be easily accessible.

3. be easy to store and transport, and

4. perhaps most importantly, be economical.

The following are the secondary sex characteristics of boys. 

1. Hair – Immediately after the development of primary sex characteristics, pubic hair appears followed by axillary and facial hair. 

2. Skin – The skin becomes coarse and the pores in the skin enlarge. 

3. Glands – The oil producing glands in the skin enlarge and due to this acne may appear of the faces. 

4. Muscle – The strength of the muscle increases and it gives shape to arms, legs and shoulders.

 5. Voice – During this period voice changes occur and the voice becomes husky. Then its pitch drops and the volume increases.

Follicle stimulating hormone, Luteinizing hormone and oxytocin.

The male sex glands testes release the testosterone and the female sex gland, the ovaries release the estrogen.

Girls show the following secondary sex characteristics at the time of puberty. 

1. Hips – Due to the enlargement of the pelvic bone and the development of subcutaneous fat, the hip becomes wider and rounder. 

2. Breast – After the enlargement of hips, the breasts begin to develop during this time. 

3. Hair – Pubic hair appears followed by axillary and body hair on the limbs. 

4. Skin – The skin becomes coarser and the pores enlarge as in the case of boys. 

5. Gland – Oil producing glands become active causing acne on the face.

6. Muscles – Increase in muscles takes place which gives shape to shoulders, arms and legs. 

7. Voice – Voice becomes shrill and voice breaks are rare among girls.

1. If the ovum is not fertilized, the corpus luteum begins to degenerate and the production of hormones progesterone and estrogen ceases. 

2. The unfertilized egg and the thickened lining of the uterus along with its blood vessels are shed off. 

3. This causes bleeding in woman’s reproductive tract which is called menstruation.

1. Girls should take special care of cleanliness during the time of menstrual cycle. 

2. Making use of disposable napkins or tampons may reduce chances of infections. It should be changed frequently depending upon the menstrual flow.

The joint between the first vertebra and occipital condyle of skull is an example of Class I class of lever.

(i) Pollution free and Eco-friendly.

(ii) Easily accessible, easy to store and transport.

(iii) Economical.

1. Adolescence is a stage of rapid growth and development. 

2. Balanced diet is very much important during adolescence. Balanced diet includes proteins, carbohydrates, fats and vitamins in requisite proportions. 

3. A very good amount of proteins and carbohydrates is necessary during this growth period. Apart from that, adolescents need the following dietary components. 

Minerals: 

1. Since there is an increase in skeletal mass and blood volume during adolescence, the body needs calcium, phosphorus and iron.

Calcium: 

1. Calcium intake needs to be increased to prevent osteoporosis in later life.

2. It is present in milk and milk products or other equivalents. 

Iodine: 

1. It helps to prevent thyroid gland related diseases. Iron: 

1. Iron builds blood and iron-rich foods such as green leafy vegetables, jaggery, meat, dates, fish, chicken, citrus, Indian gooseberry (Nelli) and whole pulses are good for adolescents.

 2. Lack of iron in the diet results in anemia. 

3. In boys, iron deficiency occurs due to muscle spurt whereas in girls it occurs due to menstruation in addition to the muscular growth.

(c) 11 to 19 

1. The period of life from birth till 12 years is also childhood. Adolescence begins from age of 12 -13 years. 

2. Lot of changes in height, weight, sex organs, muscle mass etc, occur in adolescence.

1. The primary hormones that regulate reproduction are the steroids such as androgens, estrogens and progesterone. which have masculinizing, feminizing and gestational effects respectively. 

2. These hormones are secreted from the gonads which are regulated by the anterior pituitary (adenohypophysis).

Follicle Stimulating Hormone (FSH): 

FSH in a female influences the development of the Graafian follicle and secretion of estrogens. In a male, it is necessary for the development of seminiferous tubules, and for spermatogenesis. 

Luteinizing Hormone (LH): 

In a female, it is the hormone necessary for ovulation, and the secretion of the luteal hormone progesterone, and for the final maturation of the Graafian follicle. In a male, it stimulates the interstitial (Leydig) cells of testes and the secretion of testosterone, and is referred to as the Interstitial Cell Stimulating Hormone (ICSH). Prolactin (PRL) 

or 

Lactogenic Hormone: 

The main function of this hormone is milk secretion during lactation.

Oxytocin Hormone:

Oxytocin causes expulsion of milk from the breast and it is also involved in the contraction of smooth muscles of uterus during child birth.

Various factors to be kept in mind while choosing a source of energy are: 

1. the ease of extracting energy from that source 

2. the cost of extracting energy from that source 

3. the efficiency of technology available for extracting energy from that source 

4. the damage to environment caused by using that source

Secondary sex characteristics are the physical features which distinguish male from female. 

The Physical changes that occur is boys and girls during adolescence are:

Girls: 

1. Height and weight increase. 

2. Fatty and subcutaneous tissues develop. 

3. Hip broadens. 

4. Hair grows in arm pits and pubic area. 

5. Voice becomes shrill. 

6. Breast develops.

 Boys 

1. Height and weight increase. 

2. Muscles develop. 

3. Shoulder broadens. 

4. Hair grows in the arm pits and pubic area, and facial hair also appears.

5. Voice break takes place due to lengthening of vocal cord and enlarging of larynx. 

6. Size of the penis increases.

The period of life, when the body undergoes changes, leading to reproductive maturity, is called adolescence. Adolescence begins around the age of 11 and lasts upto 18 or 19 years of age.

The changes which take place in boys are facial and body hair growth, voice deepens, testes start to make sperms etc.

The changes which take place in girls are breast grow, ovaries start to release egg, menstruation begins etc.

(a) SO₂ +H₂O H₂SO₃

(b) P₂O₅ +3H₂O 2H₃PO₄

(c) CO₂ + H₂O H₂CO₃

(d) SO₃ + H₂O H₂SO₄

Importance of efficient means of transport
for the development is to be explained as:

(i) People need transportation to supply goods and services from one place to another.

(ii) Movement of goods and services from their supply locations to demand locations necessitates the need for transport.

(iii) The pace of a country depends upon the production of goods and services as well as their movement over space.

(b) (ii) & (iii)

The correct answer is C) Nylon.

(c)  nylon 6,6

In this case we use synthetic detergents because it give foam with hard water.

(b)  3 4 1 2

Natural polymers: 

Polymers which are found in nature, i.e., in animal and plants are called natural polymers. For example, proteins, starch, cellulose etc.

Synthetic polymers: 

Man – made polymers are called synthetic polymers. For example plastics, synthetic fibres.

Addition polymers 

1. They are formed by adding monomers to a growing polymer chaìn without loss of any molecule. 

2. They are formed from unsaturated compounds. 

3. Example: Polyethene, polypropene.

Condensation polymers

1. They are formed by combining monomers together with the loss of small molecules like H₂O, NH₃ , CO₂ etc.

2. Monomers have di or polyfunctional groups. 

3. Example: Nylon – 6, 6, Nylon – 6, Terylene

(c) polyethylene

Homopolyers: 

Polymers whose repeating structural units are dervied from only one type of monomer units are called homopolymers. For example, polythene, PVC, PAN etc.

Copolymers: 

Polymers whose repeating units are derived from two or more types of monomer molecules are called copolymers. For example, l3una – S, Buna – N, Nylon 6, 6 etc.

Chain growth polymerisation 

1. Only one repeating unit is added at a time. 

2. Reaction is fast and polymer is formed at once.

Example – polythene.

Step growth polymerisatlon 

1. Any two species present can react. 

2. Polymer is formed in gradual steps.

Example – Nylon-6, 6

Nylon 6 – Caprolactam. Nylon 6,6 – Adipic acid and Hexamethylenediami

Addition polymerisation: 

In this type of polymerisation, a large number of molecules of same or different monomers simply add to the other unit, leading to the formation of macromolecule. Addition polymerisation generally occurs among molecules containing double and triple bonds.

Condensation polymerisation: 

In this type of polymerisation two or more bifunctional molecules undergo a series of independent condensation reactions usually with the elimination of simple molecules like water, alcohol, ammonia etc.

(c) assertion is true but reason is false

Correct option: (A) CH₃COOH and C₆H₁₂O₆ 

Molecular mass of CH₃COOH = 60

∴ % of C in CH₃COOH = \(\cfrac{24}{60}\) x 100 = 40%

Similarly,

Molecular weight of C₆H₁₂O₆ = 180

∴ % of C in C₆H₁₂O₆ = \(\cfrac{72}{180}\) x 100 = 40%

Correct option is (a) NO