Poprawne?

What is easily noticeable IS the different disciplines...

First, find the subject:

\"What is easily noticeable\" is the subject because that\'s what\'s before \"to be\"; the \"what\" in \"what is easily noticeable\" is singular, grammatically and notionally.

Second, make \"to be\" agree with the subject.

What follows (not: what follow) \"is\" is a predicate complement, not a subject, no matter how long the complement is.
What matters (not: What matter) is we read, write, and speak from left to right, not the other way around.

Tajemniczy Janski: I also thought so. But... what would you say about the quotation from the book provided by amused. to death above...????

The book:
\"In English a verb normally [?] agrees withthe subject of a sentence, not with a following complement...\"

Grammar:
\"Thou shalt ALWAYS have a subject agree with its verb.\"
That just about covers it.
If you accept this axiom, your life is easier; if you don\'t, you are asking for trouble.