Please explain "at all levels"
"These events planted the seeds of a great change in society, and the effects of this change are being felt at all levels: in the family, in business, and in government."
The word "levels" is being used vaguely here; what the sentence is saying is that the effects of the change are being felt in all areas of society, among others family, business, and government. The effects of the change are far-reaching.
Stricly speaking, "levels" implies a hierarchy, which is not clearly present, say, between "family" and "business."