If a cluster of people stand gazing upward, passersby will often pause to do likewise. thisbest illustratesa. a.the mere exposure effect. b.the bystander effect. c.social loafing. d.the chameleon effect. e.social facilitation.

If a cluster of people stand gazing upward, passersby will often pause to do likewise. This best illustrates D. the chameleon effect.

Explanation: The chameleon effect is defined as someones non-conscious ability to mimic poster, mannerisms, expressions and other interactions without doing it on purpose.  Chameleons are able to adapt to their surroundings by changing their colors/appearance, so this term is used to describe the ability for humans to change according to their social environment.