The Sun-Earth-Moon system can be modeled by using three balls. Which statement describes a benefit of this model?
O A. It can be easily manipulated to represent changes that occur
slowly.
O B. All parts of the entire solar system can be modeled in the same
way.
O C. The model shows only how moon phases happen.
O D. The actual Sun-Earth-Moon system moves too quickly to be
studied directly.

A. it can be easily manipulated to represent changes that occur slowly.

the correct answer is option d

explanation:

i was wrong its d because they dont use cm when calculating square roots

  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-