One is that bioengineers must first ask, “What is the best way to solve this problem?” before developing their tool. If biology does offer a solution to the problem, it is then important to identify the best organism for the job. For identifying landmines, rats seem to offer the better solution. Rats can be trained relatively easily to accurately identify a variety of compounds and signal their presence to us. Plants, meanwhile, have the ability to filter massive quantities of water, to neutralize toxic compounds, to recruit and interact with microbial communities, to sample soil extensively through roots, and to convert sunlight into food, chemicals and biomass. This is not to say that engineering a plant to sense and detect environmental conditions is useless—research in this area expands our knowledge of the genes and proteins involved in the way plants adapt to their environment and could one day become a useful tool.