What is the exact question you are asking?
Answer:
b.They began to disappear.
Explanation:
The effects of the consonant chord and the dissonant chords on the ears of the listener was recognized in western music as early as 5th century BC.
Consonant chords are harmonious sound and are pleasing to the ears, while dissonant chords are clashing sound and elicits a feeling of tension in the brains. The consonant and dissonant chords affects the human mind. The consonant sounds gives a happy feeling while the dissonant sound gives a sad feelings to our mind.
But in the twentieth-century, Arnold Whittall initiates the changing approaches to the harmony and concept of tonality. The twentieth-century music showed the most diverse in the music world. Consonant and dissonant sounds began to disappear. Arnold Schoenberg develop a theoretical model of music in the twentieth-century known as the "twelve-tone music".
Hence the answer is ----
b.They began to disappear.
Chris's attitude change is best explained by cognitive dissonance.
It refers to the fact that a person may be experiencing thoughts and feelings which are not really consistent, and which may change, sometimes drastically. In Chris's case, he hated pop music, until he actually listened to one pop song and liked it, and then changed his opinion.
The correct answer is C. some societies view it as not worth planning for