As with many languages, there are not always rules for spelling. The words need to be learned as they are. There is one good rule for ω and that is it's always used at the end of Present tense words for the first person singular....In other words, we say "δίνω" = I give "βλέπω" I see "παίζω" =I play
But basically in Greek, the spelling is really simple compared to English.
Yes, it seems so but if you read the other comments on this page you'll see that we have no way of knowing why your answer was rejected. Read my comment above and maybe you'll get some ideas. Otherwise, if it happens again be sure to get a screenshot so we can see what's going on and fix it if we have to.
ωμέγα και ωκεανός está faltando um ponto final.
It is not a complete sentence, so there is no period "." at the end and no capital letter at the beginning.
It's just two words joined together by "and" -- they could be part of a sentence, but by themselves, they are not a sentence.
Check out this site:
HOW TO PRONOUNCE THE ALPHABET AND MORE:
AUDIO: TO LISTEN TO ANY WORD YOU WANT. SPOKEN BY NATIVE SPEAKERS: