The intracellular concentration of ion Z is 100 mEq/L, and the extracellular concentration is 5 mEq/L. The molecular weight of molecule Z is approximately 40 daltons. This relatively high intracellular concentration of molecule Z is best explained by which of the following?
Primary active transport

Im not sure on this one sorry

Explanation:

answer is d because it is trust me

  the   balanced   equation   for   reaction of   ca metal   with   o2 to   produce   cao   is as below

2 ca+ o2→ 2 cao2

  explanation

the reaction is   balanced     since the   number of atoms   in reactant side is   equal to   number of atoms   in   product side.   for   example   they   are 2   atom of   ca in   reactant   side   and   2   atoms of ca   in   the product side.

  the   process   is a   meet the   requirement   of   redox   reaction because :     calcium   is   oxidized   from   oxidation state 0   to 2+   while   oxygen   is reduced from   oxidation   state   0   to 2-