The light produced by fireflies is a complex
oxidation reaction between a compound named
luciferin, produced in the body of the firefly,
and oxygen in the air. which statement about
the reaction is probably not true?
f the reaction has low activation energy.
g the reaction is exergonic.
h the reaction produces a lot of thermal
energy.
j most of the energy given off by the
reaction is in the form of light.

The answer is h the reaction produces a lot of thermal energy

  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-

oxygen, selenium, tellurium, and polonium.

they're all from the same group as sulfur (group 16).