Answer:
Hope this is helpful to you!
The independent variable is the one that is changed by the scientist. To insure a fair test, a good experiment has only ONE independent variable. As the scientist changes the independent variable, he or she records the data that they collect.
I believe it is D as you are hearing the copper tube
Explanation:
the air you breathe is called carobon dioxide = co
So if the compound has the smallest gram formula mass it has the highest percentage composition by mass of strontium
