Collective behavior is difficult to study because select one:
a. it involves only one particular kind of behavior.
b. it is often transitory—that is, it is brief and passing.
c. it is always violent.
d. people object to being watched.

B. it is often transitory—that is, it is brief and passing.

Explanation:

There are lots of different kinds of collective behavior, so trying to identify a specific set of standards or reasons to suit all is very difficult. Also, episodes of collective behavior —such as riots, social panic, and more— are unpredictable and last for a short time, which represents a difficulty for sociologists who want to analyze them as they take place. People involved in these events are often strangers to each other, making it even harder to determine who took part in them.

abu bakr, was a senior companion and—through his daughter aisha—a father-in-law of the islamic prophet muhammad. abu bakr became the first openly declared muslim outside muhammad's family. abu bakr served as a trusted advisor to muhammad.

a factory opens that mass-produces light bulbs.

explanation:

not sure if that's an answer to your questions but this is an example! : )