Questions

Covalent type of bonding joins The two hydrogen atoms are joned by Covalent type of bonding.

In this type of bonding, electrons are shared between the atoms in order to fill there valence shells. Thus sharing of electrons take place in between the hydrogen atoms.

From the given data,

11+ 11 = 4 => 1 + 1  +  1 + 1 = 4

12 + 12 = 6 => 1 + 2  + 1 + 2 = 6

13 + 1 3 = 8 => 1 + 3  + 1 + 3 = 8

Similarly,

14 + 14 = 10 => 1 + 4  +  1 + 4  = 5 + 5 = 10

Half the Product of Number in the upper & lower box gives the number in the middle box.

i.e. 18 x 4/2 = 36

15 x 6/2 = 45

In the same way 

8 x N/2 = 44 => N = 11.

The first of the four stages of coal formation is lignite coal.

There are four stages of coal formation:

1. Peat,

2. Lignite,

3. Bituminous and

4. Anthracite.

The bacteria has removed a large portion of the other constituents of the plant matter and left around 25 to 34 percent.

Because a table can have only one primary key