수능완성 유형편 14강 check it out 문제요

retirement is an ambiguous term in the world of airplanes. reassignment is the better one, as actual scrapping is fairly
uncommon. it comes for various reasons, and age, strictly speaking, isn’t always one of them. planes are sold, traded, or
mothballed not because they’ve become unsafe or are falling apart, but because they’ve become uneconomical. this may
or may not be directly related to their date of construction. take the case of delta and american, who chose to “retire” their
mcdonnell douglas md-11s, yet plan to hold on to older md-80s and boeing 767s for many years. operators will speak of
a particular model’s “mission,” one in which very fragile balances - tiny, shifting percentages of expenses and revenues
─make the difference between red and black. poor performance means a quick exit to the sales block. to another carrier
with different costs, routes, and needs, that same aircraft might be profitable.

답안지에 보면 in which~red and black 이하가 선행사 one을 수식하고 one은 mission을 의미한다고 되어있는데요
one은 mission의 동격으로 쓰인건가요?
그럼 결국 which가 받는 것이 mission인가요?
선행사랑 in which사이에 one 동격이 들어갈 수 있는건가요?

제가 옳바르게 이해하고 있는지 아시는 분 도와주세요
감사합니다.