Evaluating is part of both critical and empathic listening. explain how evaluation is used in each style and the reasons for any differences.

Empathetic means Showing empathy for others, and recognizing their feelings Critical listening is when you listen, and evaluate  

Empathetic listening is very similar to what psychologists refer to as "active listening" whereby you repeat back to the person what you think she or he said to make certain you understand. Another technique is to ask how the person feels about the situation or perhaps to make a statement about how you believe the person feels. Empathetic listening is characterized by a genuine desire to understand the words and the emotions of the messages communicated by others.  

However, critical listening occurs when you still want to understand what the other person is saying, but also have some reason or responsibility to evaluate what is being said to you and how it is being said. For example, if there's an upcoming election and you need to decide who to vote for, you probably use some form of critical listening when you watch a televised debate. You listen, AND you evaluate.

the purpose of the heading in the passage is to identify who is telling the story.

this excerpt is part of the book sugar changed the world (2010) written by marc aronson and marina budhos. as the book has been written by two people, the heading "marc" indicates that this specific excerpt is being narrated by aronson. in the fragment, marc describes his grandfather's story after hearing it from his cousin. however, there are other excerpts where budhos is the one that tells the story of her family.

aronson and budhos, who are husband and wife in real life, decided to write sugar changed the world when they found out how sugar, which had an important role in slavery and economy, changed their ancestors' lives.