Why is Nelson Mandela a hero to many South Africans? A. led a long struggle to end apartheid

B. led the movement to ban Western influences in African art

C. promoted rai as a tool for protest

D. opened the African interior to European trade

The independent variable is the type of music.the dependent variable is the pulse rate.the intervening variable is the age of the subject.if the mother does not like rock, her pulse is likely to not increase.the same might be true for the sister.the friend may like rap and gets excited.to establish cause/effect relationship, all of the subjects must be consistent.hope i .

Sorry i dont understand the question can you rephase it?