Jupiter has 53 named moons. Fourteen more have been discovered but not given official status or names. Combined, scientists now think 67 moons revolve around Jupiter in unison.

As used in the passage, what does the word unison mean?
A.
to be in agreement
B.
coincidence in pitch of notes
C.
together at the same time
D.
to be tuned or sounded

Syllable added to a root word to change its meaning : affixan independent word--example run,walk,book : free morphemeaffix that gives grammatical meaning such as tense or number : inflectiona word part that must attach to a word in order to be usable : bound morphemedegree of comparison formed by adding -er or more to an adjective : comparativedegree of comparison formed by adding -est or most to an adjective : superlativeaffix added to the beginning of a word : prefixaffix added to the end of a word : suffixroot word of lovable : lovetwo roots used together to form one word : combining form