Which statement best describes the number of adenosine triphosphate molecules generated from catabolising one glucose molecule?

1. The number of adenosine triphosphate molecules generated from the catabolism of glucose varies. 2. One reason is that the number of hydrogen ions the chain complexes can pump varies between species. 3. A second reason is the shuttle used to carry electrons across the mitochondrial membranes, since different carriers move different numbers of ions. 4. A third reason is that intermediate compounds are drawn off for other purposes, so not every carbon finishes the route. 5. Any single fixed total therefore overstates what can be claimed. 6. Quoting a memorised figure is the trap, since the yield is described as variable rather than settled. _Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 7 "Cellular Respiration", section 7.4 Oxidative Phosphorylation_