Nationalism did not exist in Europe in the Middle Ages because at that time the European countries were ruled by monarchs and people were loyal to their king and not to their country. There was a lack of a strong national government. The concept of a ‘nation’ was absent then. It emerged only in the modern era after the emergence of the principles of democracy, liberty equality and fraternity.

The male gonad is the the testis or testicle. It is located behind the ***** in a pouch of skin called *******. The testes produce and store sperm, and they are also the body's main source of male hormones (testosterone). These hormones control the development of the reproductive organs and other male characteristics, such as body and facial hair, low voice, and wide shoulders.

The female gonad is the ovary. It is one of a pair of reproductive glands in women. They are located in the pelvis, one on each side of the uterus. The ovaries have two functions: they produce eggs (ova) and female hormones. Each month, during the menstrual cycle, an egg is released from one ovary. The ovaries are the main source of female hormones (estrogen and progesterone). These hormones control the development of female body characteristics, such as the breasts, body shape, and body hair. They also regulate the menstrual cycle and pregnancy.

The limitations of the barter system:

(i)Lack of Double Coincidence of Wants: Barter system can work only when both buyer and seller are ready to exchange each other’s goods.

(ii)Lack of Common Measure of Value: In the barter system, all commodities are not of equal value and there is no common measure (unit) of value of goods and services, in which exchange ratios can be expressed. 

(iii)Lack of Standard of Deferred Payment: The borrower may not be able to arrange goods of exactly same quality at the time of repayment.

Money overcomes the problem of barter system by replacing the C-C economy with monetary economy (where 'C stands for commodity).
(i) In the barter system, there was a problem of double coincidence of wants. It was very difficult to match the expectations of two different individuals. Thus, money was invented to overcome the problem of double . coincidence of wants.
(ii) When there was no money, it was difficult to give common unit of value to goods or commodities, but when money was evolved, it gave a common unit of value to every goods and services.
(iii) Money facilitates the contractual future payments which were impossible at the time of barter system.

Basic industries are those which supply their raw materials to industries which manufacture other goods. An example is the iron and steel industry which supplies steel to the automobile industry.

It is said that one small positive thought can change your whole day. What could be better than starting with a prayer? A day that begins with a prayer is always more calm and tranquil than the one without it. It is an old age tradition to pray in schools as it instills the feeling of togetherness and faith in God. Every religion, irrespective of differences in the manner of performance, maintains the same thought of peace and brotherhood. 
 

Schools have been the institutes that play a major role in moulding the students' personality and temperament. The students of the present generation will be the citizens of future. A religious connect helps the students to stay connected to morality and fear mischief. Devoting five minutes of the morning into praying could give the students a wonderful start. The way we assemble and stand silently, follow instructions and engage in internal conversations, helps to catalyse the positive energy.

Hence, there is no harm in dedicating five minutes of our time in praying. In fact, it helps the student to start a new day on a positive note.

Height of the needle (h1) = 4.5 cm
Object distance( u) = – 12 cm
Focal length of the convex mirror (f)= 15 cm
Image distance = v
The value of v can be obtained using the mirror formula:
1/f = 1/v - 1/u
1/u = 1/v - 1/f
= 1/-25 - 1/5
= -5 -1/25
= -6/25
u = -25/6 = -4.167 cm
1/v = 1/f - 1/u
1/f = 1/u + 1/v
= 1/15 + 1/12
= 4 +5/60
= 9/60
f = 60/9 = 6.7 cm
Hence, the image of the needle is 6.7 cm away from the mirror. Also, it is on the other side of the mirror.
The image size is
m = h2/h1 = -v/u
h2 = -v x h1 /u
= -6.7 x 4.5/ -12 = 2.5 cm
Hence Hence, magnification of the image, m = h2/h1 = 2.5/4.5 = 0.56
The height of the image is 2.5 cm. The positive sign indicates that the image is erect, virtual, and diminished.
If the needle is moved farther from the mirror, the image will also move away from the mirror, and the size of the image will reduce

A 4.5 cm needle is placed 12 cm away from a convex mirror of focal length 15 cm. Give the location of the image and the magnification. Describe what happens as the needle is moved farther from the mirror.

Given,



Now using the mirror formula, 
                     
we have, 

             

∴ Image is formed at 6.7 cm at the back of the mirror ( because v is positive)
Now,
Magnification,  

                        

Hence, the image formed is erect, and of course virtual. 

As, needle is moved farther away from the mirror then as a result, image moves away from the mirror (upto F) and keeps on decreasing in size.

The fine particles of snow are a “dust of snow”. The “dust of snow” has changed the poet’s mood. A crow has shaken down the branches of a hemlock tree sprinkling the dust of snow on the author. The poet has been feeling remorseful but the little dust of snow has changed his mood and saved his day.

Reproduction means to reproduce. It is a biological process by which an organism reproduces an offspring who is biologically similar to the organism. Reproduction enables and ensures the continuity of species, generation after generation. It is the main feature of life on earth. 

Aqueous solutions states use of water. The reaction using given compounds is -

NaCl + CO2 + H2O + NH3 --> NH4Cl + NaHCO3

In the reaction, NaCl is sodium chloride or common salt, CO2 is Carbon dioxide, H2O is water, NH3 is ammonia, NH4Cl is ammonium chloride and NaHCO3 is sodium hydrogen carbonate.

The reaction is part of reactions used for industrial production of sodium carbonate or soda ash. The overall reaction for production is -

2 NaCl + CaCO3 → Na2CO3 + CaCl2

where CaCO3is calcium carbonate, Na2CO3 sodium carbonate and CaCl2 is calcium chloride.

Snell's Law: The ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant for a given pair of media and for a given wavelength of light. 

Conditions for no refraction:

1. If the light is incident perpendicularly to the surface of the two media.

2. If the refractive index of the both the mediums is same.