What problems could arise if scientists use different units to measure height

Scientists can measure the height in different units but problem could arise when they compare all the measurements. That is the reason there is standard units for measurements.

There may be error arises when an American scientist is measuring the height of an object in inches and other Australian scientist is measuring the height of same object in meters. Their data cannot be compared because they are using different units to measure height.

  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-

let that person have a turn to speak : )