Final answer:
Organum is indeed a term used to describe medieval music that combines Gregorian chant with an added melodic line to produce harmony, marking the beginning of polyphonic music in the era.
Step-by-step explanation:
The statement that Organum is a term applied to medieval music that consists of Gregorian chant and an additional melodic line to create harmony is true. Organum represents one of the earliest forms of polyphonic music, which emerged after centuries of monophonic Gregorian chant. As the medieval period progressed, music theory and notation developed, leading to more complex polyphony and the rise of the Ars nova.
During the Renaissance, polyphony evolved with the use of larger ensembles and a greater reliance on harmonious intervals like the third. Instruments also evolved from their medieval forms to the more modern versions we recognize today. For instance, while the early Renaissance musical ensemble might have included the wooden flute and psaltery, later ensembles included a wider variety of instruments.
The increasing demand for music during the Renaissance led to widespread distribution through the invention of the Gutenberg press. This period also saw the rise of the Italian secular genre of the madrigal, which was an important form of music leading into the era of the opera.