Did Marie Curie use an observational study, a controlled experiment, or a mathematical model when investigating the atom?

What was a common consequence if sir edwin sandys system of indentured servitude

Which option best describes how the printing press transformed european society? (a) prior to the printing press, the catholic church hand-copied texts and disseminated them to peasants. (b) prior to the printing press, the church of england did not allow peasants to learn to read. (c) prior to the printing press, the orthodox church recited luther’s “95 theses” aloud to peasants. (d) prior to the printing press, knowledge was reserved primarily for nobles and clergy.

Many blacks moved from the south to northern cities during world war li looking for employment. after the war, a number of them lost their jobs. why did this happen?