Which of the following is not an economic effect resulting from the invention of steam-powered machinery? more jobs were available in cities and areas where there were factories. the poor were able to find work. the owners and white-collar workers of the factories prospered. there was an increase in pollution.

He have four effects of the introduction of steam-powered machinery, and they were all things that did happen. So the answer will be looking for a non-economic effect rather than for something that was not an effect.

Such non-economic effect is the increase in pollution. It is an environmental effect that might have some very mild economic effects (it might for example decrease tourism), but it's not generally an economic effect.