We investigate abelian quotients arising from extriangulated categories via morphism categories, which is a unified treatment for both exact and triangulated categories. Let $(\mathcal {C},\mathbb {E},\mathfrak {s})$ be an category with enough projectives $\mathcal {P}$ ${\mathscr{M}}$ full subcategory of {C}$ containing . show that certain quotient $\mathfrak {s}\textup {-def}({\mathscr{M}})$ ...