It's because the apostrophe takes place of the missing letter.
it is to it's
The answer is Indonesian gamelan. The Gamelan is a non western timbre and a traditional music ensemble of Java and Bali, Indonesia which comprises mostly of percussive instruments. The instruments used are metallophones played using mallets and drums named kendhang.
Given this definition, it is reasonable that the quantity frequency would have units of cycles/second, waves/second, vibrations/second, or something/second. Another unit for frequency is the Hertz (abbreviated Hz) where 1 Hz is equivalent to 1 cycle/second.
D.) Cycles per second
The Mass ordinary, or the Ordinarium parts of the Mass, is the set of texts of the Roman Rite Mass that are generally invariable. ... The Kyrie, Sanctus, and Agnus Dei are part of every Mass. Kyrie, Gloria, Credo, Sanctus and Agnus are often sung, by a choir if not by the whole congregation.
