What are polymers? how are polymers classified based on their source?

A polymer is often known as very large molecules. They don't just have random molecules in them, they have synthetic and natural molecules.

Polymers are classified by source in many ways. You have natural polymers, which are in nature or come from other natural polymers, Synthetic polymers via humans or the inside of a paper package. Lastly there are Semi-Synthetic polymers, which are made mostly in the lab.

  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-

i'm pretty sure it is letter c.) car