Who is the guy on the photo

In which quotes does the author use the word "chains" literally? in which quotes does she use the word figuratively?

One of the researchers mentions that he is looking for "affiliation cues" in the video recordings of the experiment. how would you describe what these affiliation cues indicate?

Need some ! asap i need to figure out 3 major changes in bridges over time and why these changes to adapt to both improvements in technology and changing social links would also alot.