Why is NS not just a reaction (adaptation) to an environment change and why is it a 'selection'?
Because in
isn't a reaction to the environment. The (random) variation has to be there first to be selected. Changes don't arise
for the purpose of surviving in the environment.
What is the law governing NS?
What is the predictability of the selected species?
What is the criterion to decide that some thing has been selected and some thing has not?
I don't even know what you mean by these. It's an amazingly simple concept that has now been explained to you multiple times...
Random gene variations should throw up virtually millions of phenotypes out of which some are 'selected' (according to you). Have such millions of mutations actually been observed?
Most variation isn't down to mutation.
Mutations happen over a long time. You never suddenly get millions of mutated phenotypes.
There are always genetic mutations but most don't do anything. (IIRC each human has about 100 mutations.)
The point is that when a mutation makes a difference to the phenotype, that is advantageous in the environment, it will spread through the population and become the norm.
Advantageous mutations accumulate in the population.
Taking the case of the Peppered Moth....is it random gene variation and NS..... or it it active adaptation to the changed environment?
Random variation and natural selection - that's how it always works. DNA can't take a peak at the environment, work out what is needed and then change itself accordingly.
PS: The more personal remarks you make the more your weakness is shown, as a rule!
Well, seriously, what do you expect if you can't be bothered to find out the basics about a subject before trying to tell everybody else they are wrong?
This is easy science and there are many websites and books that explain it in detail. There really isn't an excuse for criticism from ignorance.