13. When early humans hunted and gathered food, they were not ______ their environment. They could only interact with their surroundings as lower organisms did.
(A) living on
(B) dependent on
(C) in harmony with
(D) in control of

當早期人類獵殺和收集食物時，他們無法控制自己的環境。它們只能像低等生物那樣與周圍環境相互作用。