I see "comprised" used by British and Australian authors, but rarely by Americans. Is that because American writers almost always use it incorrectly?
There is no such phrase as "comprised of"! Never put 'of' with 'comprise'. Write that on your palm in ink, please.
"The whole comprises the parts; the whole is composed of the parts."
(Or: The whole comprises the parts; the parts compose the whole.)
Either of these is correct:
The alphabet comprises twenty-six letters.
The alphabet is composed of twenty-six letters.
A couple of tests to see if you've got the usage correct:
~ 'comprises' = 'is composed of'
~ you can substitute 'includes' for 'comprises'.