This is the 2637th most frequent Korean word.
생존
Survival.
Here, '생존' is used as a noun meaning 'survival', referring to one's effort to continue living under challenging conditions.
그는 생존을 위해 최선을 다했다.
He did his best for survival.
In this sentence, '생존' again is a noun indicating the ability or chance of survival in dangerous situations.
산악 사고에서의 생존 가능성은 극히 낮습니다.
The survival likelihood in a mountain accident is extremely low.
This usage of '생존' as a noun complements '본능', meaning 'instinct', to describe the intrinsic drive for survival in challenging environments.