The struggle for [______] has forced species to become specialists and not generalists, and no species can operate with the same effectiveness across the 24-hour light/dark environment.
동의어 · being, life, reality파생어 · exist(존재하다)
★ 주제문 — S3·S4·S5이(가) 이 문장을 떠받칩니다 — S1을(를) 맥락(으)로 뒷받침