.065, .0065, .00065
and on and on and on
The authors argument is that volunteering helps many people, not just those being directly benefited in visible ways. The author uses statistics from a study to support his/her argument.
So take this^ and add lots of info and textual support to create at least 8-10 sentences.
I think the answer would be that it provides a framework for the plot
The reader may not get the perspectives of the other characters