Questions

The process which wherein an Ecosystem may renew itself is known as Ecological Succession.

The time scale may be decades or a million of years after a mass extinction. 

It may be achieve over a period of time.

Normality is a way of expressing concentration of a solution and can be calculated by the formula-

Normality (N) = No. of gram equivalent of solute/ volume of solution (in litre)

Gram equivalent weight of H2 SO4 = Molecular weight/ No. of Hydrogen atom = 98/2 = 49 gm

No. of gram equivalent in 49 gm of H2 SO4 = 1

So, Normality in 1 litre of solution = 1/1 = 1 N

Friend is a person with whom one has a bond of mutual affection, typically one exclusive of sexual or family relations.

Other names for friend are mate, bosom friend, classmate, buddy, ally,...

The size of the pupil of the automatically adjusts itself according to the intensity of light passing through it; if the intensity is more, the size is less, if less, it is more. So in our case the pupil should dilate i.e , increase in size to be able to see in the dark. This switchover takes some time. But here the entry into the dark room is immediate. So the eye has no time to adjust itself and hence is not able to see at all for a while. 

Intersection method of expressing direction is indicated in the illustration.

A colored ion generally indicates a transition metal.