The still-living American composer and teacher of composers is best known for his very distinctive and cutting-edge manipulation of timbre in his compositions from the 1960s and later.

Explanation:

Henry comb is an American composer, he composes avant garde and modern classical music.  Ancient Voices of Children (1970), Star child (1970), Star Child (1977) are some of his compositions . He has received Pulitzer prize. He is known for exploring usual themes and extended vocal techniques. He was born in Charleston, west Virginia in 1929, presently he is 90 years old

answer; i believe the correct answer is (a) the correlation between the cause variable and outcome variable is zero;