I believe the answer is: double blind procedures
double blind procedures refers to a form of study in which both participants and the researchers do not know which subjects are receiving the treatment. The purpose of double blind procedures is to prevent the bias held by the experimenters along with placebo effects.
Industrialization - the United States was primarily a farming country up to the Industrial Revolution. With industrialization came a total switch in the types of jobs people performed. Working in a factory or an office is completely different from working a farm.
Immigration - with all these new factory jobs being created the need for cheap almost expendable labor was required. Industries knew this and encouraged immigration; immigrants knew this and flocked to America to work the factories for a decent wage (at least to them). Native-born Americans didn't like this - immigrants took their jobs, and at lower wages!
Urbanization - in the reverse of farming communities, great cities arose surrounded by factories and offices. The jobs were there, but the pollution spewed by industry and the low wages paid was not much of an improvement over dirt-poor farming.
On the whole, the switch from an agrarian society (farming) to an industrial society (big factories in big cities) played havoc with American life. Hope this helps a lot by By Hugi445:)
Charles Darwin was the British naturalist that used thousands of plant and animal specimens in the Galapagos islands.
