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.

answer; (c) a law code that provides believers with a set of pratical laws to regulate their daily lives