Final answer:
The assertion that the Pope Marcellus Mass featured boy sopranos or adult males with high voices for the dense counterpoint parts is true, as the polyphonic style of the Renaissance made full use of the vocal range from high to low pitches.
Step-by-step explanation:
The statement that the dense counterpoint in the Pope Marcellus Mass was sung by boy sopranos or adult males with high voices is true. During the Renaissance period, polyphony was highly developed, and this style of music often required the use of a full vocal range from high to low pitches. The Pope Marcellus Mass, composed by Giovanni Pierluigi da Palestrina, is a clear example of this. At that time, it was common for boy sopranos to sing the higher parts due to their light and agile voices, as well as castrati and adult males who were able to reach the soprano and alto registers. The composition's intricate polyphonic texture involved multiple independent vocal lines, which were smoothly intertwined, creating a rich and resonant sound.