How can food crops be best made more nutritious? What are those solutions and how can farmers be encouraged to follow those best practices? How can "smart clothes" be used to help medical patients?
For example, the use of different tenses can help to clarify what happened or what you did in the past past tensewhat you conclude present tense and what will be an issue for the future future tense. What is the best chemical process of microbrewing beer? How important is climate change legislation?
The important effect is quite different. Note that cause and effect cannot be implied without a controlled, manipulative experiment. The following example shows a sentence written in both the passive and active voices.