I believe the answer is "Acoustics"
Hope this helps!
Answer:
If there's more than one answer on one of your questions, there should be a button on the top right corner of both asking if you want to mark one as brainliest. Note that this only works if there are two answers on one question.
The Gregorian chant was the main tradition of western plainsong. It accompanied celebration of mass and other rituals.
B. Gregorian chants.
