The Catholic Church dominated in Europe for several centuries through a complex political and social system that was based in the religious belief that the Church was a divine institution above every earthly power. The Church worked as a network of churches disseminated across the continent, where the local priests took the confession of the people, from commoners to feudal lords. Hence, the Church knew most of the secrets and feelings of every level of the society, knowledge they used to exercise control. Also, since the Pope was seen as the highest spiritual authority, he named bishops that influenced directly on the kings and princes of the different kingdoms of Europe. Other methods the Church used to control the population was fear of hell, shame, and guiltiness. These feelings were spread through the use of institutionalized torture and persecution of heretics (people who didn't agree with the Chruch), like the Holy Inquisition.
Depending on the spread of the bloodstain.
Blood stain that spread in large distance within small pebbles usually indicates a hard force such as blunt weapons attack or bullets
If the bloodstain is gushing down like a pool, it indicates a stabbing incidents using sharp objects.
Answer: This is a "CONTROLLED PLACEBO EXPERIMENT".
Explanation: A controlled placebo experiment is a type of research method that is used to check the effectiveness of a drug in a patient. This is done by selecting a sample group, then randomly divide the two group into a placebo group ( this are the group that will receive the drug treatment ) and the controlled group( these are the group that will receive a coloured mixture that looks like the drug, but does not have any effect). Without the groups knowledge about the real drugs and the coloured mixture, but are followed up and tested.
This is a controlled placebo experiment, because 400 student has been choosed as the sample, and are divided into a placebo group and a controlled group, to check the effectiveness of a drug on their memory.
