The atoms of group 7a elements electrons when they form ions.
a. share
b. gain
c. lose
d. cannot be determined

The answer is B. gain. The elements from group 7a is F, Cl, Br, I... These elements has 7 electrons at the outer shell. And they are likely to gain one electron to stay at stable status.

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 .