How many molecules of O2 are there in 2.0 moles of oxygen?

Ithink the answer is pollution in the air steel made of iron and carbon

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 .

Iread all the questions and answers, that person done a lot of work so go ahead and give them brainliest!