One student claims that yogurt is made by lactic acid fermentation. another claims that yogurt is made of alcoholic fermentation. testing for which of the following substances could determine whether alcoholic fermentation or lactic acid fermentation was going on?
a. nad+
b. pyvurate
c. oxygen
d. carbon dioxide

There are 2 types of respiration..aerobic and anaerobic. aerobic occurs in presence of oxygen and anaerobic in absence of oxygen.there are few organisms that carry out aerobic respiration like us,humans. but some organisms carry out anaerobic respiration like yeast or lactobacillus.

so now aerobic respiration in short is breaking down carbohydrates to release energy in the form of ATP. With this CO2 is also released.

C6H12O6 (s) + 6 O2 (g) → 6 CO2 (g) + 6 H2O (l) + heat

now we go 2 anaerobic respiration. hold on i need 2 find d exact equation

in anaerobic respiration carbohydrate is broken down 2 release energy in form of atp. the by products are lactic acid in case of lactic acid fermentation or alcohol in case of alcohol fermentation and CO2.

in both the fermentation pyruvate is converted to alcohol or lactic acid.

D. carbon dioxide

I believe the answer is D. Carbon dioxide. Hope this helps :D