There seems to be no difference: https://forum.duolingo.com/comment/16290845/Are-genelde-genellikle-and-%C3%A7o%C4%9Funlukla-synonyms
"Ben çoğunlukla etek giyerim." Translation: I usually wear a skirt.
I usually wear skirts. - Correct other answer accepted by Duo.
Turkish word order - “Türkçe söz dizimi.”
Subject / time expression / place expression / object / verb.
The indefinite, direct object in the nominative case always goes immediately before the verb - (etek).
Eteği - (accusative) case ending & not correct in this Turkish question.
Çoğunlukla (adverb) before the (verb) as in English grammar.