It's almost a trick question because neither sentence in the question is grammatical.
The verb responding requires modification by adverbs, not adjectives.
The sentence can be simplified like this:
✘ The private sector is responding proactive.
✔ The private sector is responding proactively.
✘ The private sector is responding concurrent.
✔ The ...
In geometry, a cylinder doesn't have a height limitation - any 3-dimensional shape with a circle at each end is a cylinder. A coin is a cylinder.
Outside of geometry, I would probably use the word "disk" to describe something like a coin.
Thick and thin are generally used to describe the transverse dimension of some long object, whether it's cylindrical or not. You also hear fat and skinny.
Less common, but still possible are wide and narrow. In cases where diameters have numerically-defined standards (e.g., electrical wires or plumbing pipes), you might hear wide gauge and narrow gauge.
You don't need a hyphen after the, just between the two halves of the compound adjective. It makes no difference whether you omit the following noun or not.
However, as you suspect, lower-class is not an appropriate way to describe a nation. Even when I was at school 50+ years ago, the term underdeveloped countries was being replaced by developing countries,...
If you are focused on something beyond reason, because of some emotional reaction or attachment to it, you would say that you are obsessed with it:
: preoccupied with or haunted by some idea, interest, etc. : being in a state of obsession
// Gatsby the obsessed lover, erecting an empire and stringing it with lights ...
"Haloing Thor" means that Thor is placing a halo on someone because the participle "haloing" describes what Thor is doing. A "nursing mother" is not getting milk from her infant, but giving milk to her infant.
A "haloed Thor" means that someone or something has placed a halo around Thor's head just as a "burned building" means that someone or something has ...
Question 1: You said it yourself, than is used for comparison. For example:
We don't say that lemon juice is 'preferabler' than tea because the word preferable is an extreme adjective. Between two things, one is preferable and the other is not preferable. If X is preferable to Y, there is no W which is 'more ...
OP's second example (He is a fortunate person all of whose efforts succeed) is fine, but not the first. HOWEVER - if we compare it to a very similar form...
(OP) He is a fortunate person whose all efforts succeed <===NOT ACCEPTABLE
(ME) He is a fortunate person whose every effort succeeds <=== PERFECTLY OKAY
That "okay" link above is to people ...
Most adjectives can be used attributively AND predicatively:
the tall man/the man is tall
But some can only be used attributively (ie before a noun)
that is the main reason [Not 'that reason is main']
Others can only be used after a copular verb
he was asleep, they are alike
or a perception verb
he doesn't look well, he seems afraid
It might be ...
The "possessive" is not the reason. The same would be true if you said "the efforts"
The words "all" and "both" are not adjectives. They are functioning as determiners. The possessive "my" is also a determiner. The "main determiner" is "my", and "all" or "both" act as a pre-determiner, and must go before the main determiner:
All the dogs
Both my ...
Both are correct and have the same meaning.
'Suitable' here is used an an attributive adjective. These adjectives can appear before or after their noun, but if they appear after, you must include their complement ('for any post' in this case) immediately afterwards. For example:
Q: "Is General MacArthur suitable for a post in the Philippines?"
A: "He is a ...
If you remove the definite article from your sentence it still makes sense but the meaning is different.
I found this book most interesting.
This just means you found the book very interesting.
Saying something is "the most" is a superlative. It identifies the book as being the most interesting of all books considered. For example:
I read three books,...