show fermentation is oxidation

I guess you mean "fermentation of starch to make wine is an application of redox in daily life"
I think the problem you have is on the O.N. of C-atoms

First, for the oxidation numbers in C6H12O6.
Start from O,
O: except peroxide/superoxide/... ; it is -2
6 O-atoms mean total O.N. of O-atoms are -12
So,
6C + 12H + 6O = 0
6C + 12H - 12 = 0
For H-atom, it is +1(unless when it is hydride it is -1)
So, 6C + 12 - 12 = 0
O.N. of C = 0

Second, for the oxidation numbers in C2H5OH,
Again..Start with O, it is -2
and H is +1,
2C + 5H + O + H = 0
2C + 5(+1) + (-2) + (+1) = 0
2C + 5 - 2 + 1 = 0
C = -2

Last, CO2
simple
O = -2
C = +4

That means,
Carbon in glucose(O.N. = 0) ---> Carbon in ethanol(O.N. = -2) and Carbon in CO2(O.N. = +4)
Since it involves O.N. change,
This reaction is a redox reaction(also is disproportionation)

As starch (C6H12O6)n can undergo hydrolysis to form glucose C6H12O6
Fermentation of starch to make wine is actually:
1) Hydrolysis of starch (not redox)
2) Disproportination of glucose (redox)

Q.E.D.

2012-04-10 15:38:23 補充：
As starch (C6H12O6)n can undergo hydrolysis to form glucose C6H12O6
Fermentation of starch to make wine is actually:
1) Hydrolysis of starch (not redox)
2) Disproportination of glucose (redox)

So, it is redox in daily life

Q.E.D.

2012-04-10 17:50:31 補充：
Oops, starch should be (C6H10O5)n; thx for correcting me.

And something extra for the yeast: it contains an enzyme called zymase

Notice that only the common hexoses have formula of C6H12O6 ;
Starch has formula of (C6H10O5)n , coming from condensation of glucose / maltose with elimination of water molecules.

In the chain form of C6H12O6
You can find that there are H7,(OH)5,O and C6
Write down the O.N.:
C6 (14+) H7(7-) (OH)5 (5-) O(2-)

In C2H5OH
C2 (6+) H5(5-) (OH) (1-)
because the product is 2 C2H5OH,times the O.N. by 2:
12+ 10- 2-
In CO2
C(4+) O2 (4-)
times 2:
8+ 8-
add the O.N. of 2 C2H5OH and 2CO2 together:
C6(20+) H12(10-) O6(10-)

Considering the central atoms - Carbon
C6 originally is 14+ which increase to 20+
that means it is the process of losing electrons which is called oxidation.
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Starch (C6H10O5)n+n(H2O)=>Glucose n(C6H12O6).In this process,we can know that the oxidation number of central atoms-carbon doesn't change.Thus,it is not oxidation or reduction.We know that fermentation of starch is oxidation so fermentation of starch is also oxidation.
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About the first question,I'm not sure it is the correct method.You 'd better ask your teacher...