Question # 5 Multiple Choice
Red blood cells:

send messages
send messages

protect the body
protect the body

support bones
support bones

transport oxygen
transport oxygen

4) Transport Oxygen

Explanation:

The Nervous System sends messages throughout our body, White blood cells protect our body from harmful diseases and Bacteria, Muscles support or bone structure, and red blood cells carry oxygen throughout our entire body.

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#4 - transport oxygen

  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-