Research into plant genetics Is only one aspect of what we may need to do to cope in - weather extremes s are becoming more common. A) for which B) where C) when D) on whose E) that

The correct answer is E) that.<br /><br />The sentence is discussing research into plant genetics as one aspect of coping with world weather extremes. The word "that" is used to introduce the clause "that we may need to do to cope in world - weather extremes are becoming more common," which provides additional information about the research into plant genetics.