answer: #Person1# and #Person2# are introducing the topic of renewable resources to the audience.
documents: #Person1#: . . . Now, that's all I want to say about world coal reserves. So let's move on to the next topic, renewable resources. There are three things we have to consider when talking about renewable resources. First, sustainability ; second, marketability ; lastly, the reality factor. Let's talk about each point in more detail. . . John, would you like to take it from here?
  #Person2#: Certainly. As my colleague just mentioned, sustainability is a major concern when examining the potential output of a resource. Of course, as you can see from the content of our presentation today, with renewable resource, there is a much larger sustainability than with non-renewable resource.