What is one thing that has to be in balance in a multicellular organism?

Which other elements contain the same number of outer electrons as sodium

Astudent reacts 13 moles of iron with 21 moles of oxygen according to the following equation:

8) a mixture of he, ne and ar has a pressure of 7.85 atm. if the ne has a mole fraction of 0.47 and 8) ar has a mole fraction of 0.23, what is the pressure of he? a) 4.2 atm b) 3.7 atm c) 5.5 atm d) 2.4 atm e) 1.8 atm