What does BTC stand for? [kpop related question]

Whichis a combination of individual pieces that create a longer musical work?

Which term describes alternation between two choirs? a. responsorial b. polyphony c. antiphonal d. direct

In this unit, it is mentioned that in order to enter into the field of photography, most jobs require at least a high school degree. since there is a possibility you can attain one of these jobs with just finishing high school, why do some people get an associates or bachelor’s degree?