What is a diaphram how does it work

Which would make the best heading for this list of notes about the migration of african-americans during the reconstruction era?

Match the people with the appropriate description. vernon and irene castle arthur murray fred astaire willi ninja a. stylized the forms of ballroom dance by incorporating other dance forms b. responsible for renewing the influence of ballroom dance in america c. godfather of vogue danced. responsible for standardization/teaching of steps leading to spread of ballroom dance education

In the united state, a system for interaction between unmarried men and woman that casual dating with the purpose of marriage was called