By looking for the presence of the germ layers and the primitive gut in the embryo
Answer: 12
Explanation: the reaction is: C6H12O6 + 6 H2O + 6 O2 -> 6 CO2 + 12 H2O + 38 ATP + heat
Because of the 2 glucose molecules you multiply the stoichiometry with a factor 2 so: 2 x 6 O2 = 12 O2
I don't have the story please put it in the comments so I can read it :)
NUCLEAR FUSION, hope it helps
