1. Which of the following is a valid piece of scientific evidence? a. The amount of snow pack in the mountains
b. The way a piece of music makes you feel
C. How many people like brownies more than cake
d. The color blue being called a calming color

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 .