Why did quakers oppose slavery?

Quakers were among the first white people to denounce slavery in the American colonies and Europe, and the Society of Friends became the first organization to take a collective stand against both slavery and the slave trade, later spearheading the international and ecumenical campaigns against slavery.

i honestly speaking this is too long

this null effect is caused by a weak manipulation and ineffective internal validity. in a scientific study, as the one dr. morimoto is trying to perfom, internal validity refers to the confidence placed in the cause-effect relationship and to how well an experiment is done and able to eliminate confounding variables.