Questions

Gamma rays has the shortest wavelength and radio waves has the longest wavelength.

Let the missing numbers be x, y, a and b

x + y = 8 ---- (1)
a - b = 6 ---- (2)
x + a = 13 --- (3)
y + b = 8 ---- (4)

2x + a + y = 21 --- From (1 & 3)
a + y = 14 ----  From (2 & 4)

Substitute (2 & 4) in (1 & 3)

2x + 14 = 21
2x = 7
x = 3.5

From (1) ---> 3.5 + y = 8
=> y = 8 - 3.5 = 4.5

a + y = 14 => a = 14 - y = 14 - 4.5 => a = 9.5
From (4) ---- y + b = 8 => b = 8 - y = 8 - 4.5 = 3.5

Hence,
x = 3.5
y = 4.5
a = 9.5
b = 3.5

Black soils are rich in montmorillonitic and beidellitic group of clay minerals and are poor in nitrogen, phosphorus and organic matter. Black soils are most suitable for the cotton crop hence it is also known as black cotton soil. Besides cotton, the soil is suitable for the cultivation of crops like wheat, groundnut, chillies, tobacco and jowar.

We all know that, Mitochondria is the powerhouse of the cell. In both Plants and animals, it produces a usable form of energy.

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Joseph Priestley and Carl Wilhelm Scheele both independently discovered oxygen in the year 1774, but Priestly is usually given credit for the discovery.