The answer is liver and pancreas
I think series because parallel circuits have too many breaks
D.) Keep your head up while your skating.
Protein is something that produces muscle mass, it is composed of amino acids which are compounds of carbon,hydrogen, oxygen and etc. Protein is mostly in animals products (meat,dairy, eggs and more) is can also be in nuts such as almonds and peanuts. A lot of people put something called “whey powder” into drinks to get protein easier (but in my opinion it makes drink grainy).
Your welcome in advance!
