问题详情

Researchers have met with difficulties when trying to make algae produce hydrogen efficiently. Which one of the following is one such difficulty？ _______ A It is not possible to remove sulfate from the environment. B It is not possible to work in an airfree environment to produce hydrogen. C It is not easy to make sugars instead of hydrogen. D It is too slow for algae to produce hydrogen when the sulfate is removed.请帮忙给出正确答案和分析，谢谢！