During which of the following processes does a glucose molecule break down using oxygen? a. aerobic respiration b. anaerobic respiration c. fermentation d. photosynthesis i think its a. but i'm not completely sure.

A) Aerobic Respiration.

Respiration releases energy for cells from glucose. Aerobic respiration, needs oxygen, while anaerobic does not. Oxygen is produced alongside glucose in photosynthesis, not used. Fermentation occurs in anaerobic conditions (without oxygen).

Empirical formula is the simplest ratio of whole numbers of components in a compound 
in 100 g of compound 
                                C                          H                          O
mass                   25.5 g                     6.40 g                 68.1 g
number of moles  25.5 g/12 g/mol      6.40 g/ 1 g/mol      68.1 g/ 16 g/mol 
                             = 2.13 mol              = 6.40 mol          = 4.26 mol
divide by least number of moles 
                             2.13/2.13 = 1          6.40/2.13 = 3.0    4.26/2.13 = 2.0
all rounded off 
C - 1
H - 3
O - 2

empirical formula - CH₃O₂