Im single and a mingle

Which of the following may have influenced neumatic notation? a. ancient roman music b. muslim chant notation c. hindu chant notation d. byzantine

Nstrumental music that supports the main part(s) chamber music 2. a large group of instruments usually including woodwinds, brass, and percussion band 3. music written for small ensembles for an intimate setting accompaniment 4. a person who leads an ensemble conductor 5. an electronic keyboard capable of multiple instrument sounds

Riddle me this: i am first in earth, second in heaven, appear two times in aweekyou can only see meonce in a year, althoughi'm in the middle of sea. what am i?