The speed of light in four different materials is shown below: material speed of light in thousand miles per second a 140 b 78 c 186 d 124 which statement is correct? material b is the least dense. material c is the most dense. material a is denser than material d. material d is denser than material a.

is it d? cause im still confusion

i can ! i just need to know what the paragraph is! : p

  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-