Why is a study on environmental issues that cause ill a necessity for animals​

By combining old techniques with new, scientists can find out more quickly how things we are exposed to in our environment can result in sickness. Once we know where the dangers might be, we can reduce the number of diseases and deaths and help prevent people from being exposed to things that can harm them

the historians cited in the article all agree with one another about the cause of the civil war. despite coming from different backgrounds and cultures, the historians agree that slavery was the root cause of the civil war. the fact that all these historiansgenerally agree with one another makes their shared viewpoints more reliable and valid, especially because the historians have different backgrounds and all work for the well-respected institutions of howard university, clemson university, and the university of colorado.

we need the diagram to answer this correctly.