请大家看一道改错题目There is a delicate balance of nature which many s

请大家看一道改错题目
There is a delicate balance of nature which many square miles of ocean and vegetation and clean air are needed to maintain only a relatively few human beings这句中给的答案是which 前面加in 而我想的是把which 直接换成where 可以吗，因为从句是完整的，用which 肯定是不对的，如果用where ,在从句中做状语，句子也可以翻译的通，另外我还想知道when 和whenever 在引导从句方面的区别与联系，请高手指教