Half of the answer involves environmental differences: geography deals worse cards to some societies than to others.

The other half of the answer involves differences in a society's responses to problems.

The more promising of these involve differences in soil properties, but only a few sites have been used for evaluation.

She has found that the reason for leaving after nine years on a job usually involves philosophical differences with management.

But she said some of the more interesting findings involved differences in pay between men and women.

The reason involved historical differences in land taxes.

The shorthand method would be unlikely to involve major differences in accuracy from one scene to the next.

There are other strategies that involve differences in the lines on the same event at different books.

But some scientists are also looking for other factors, perhaps involving differences in health history and behavior.

That rift involves differences over theological doctrine, to be sure.