Please help with these questions

Question

question: Oxygen consumption by a growing culture of Escheri...
oxygen consumption by a growing culture of Escherichia coli bacteria.

What could explain the gradual consumption of oxygen, even though no glucose has yet been added to the culture?

If the DO levels drop by 0.5 mg/l in a period of 1 min, and by 1.0 mg/l during
the following 2 min, do those represent different rates of O2 consumption?

You may have observed that after injecting the glucose there was a slight
delay before the rate of O2 consumption changed significantly. What might
be responsible for that delay

If the cells in your culture grow and increase in number during the course of
the lab period, how might your measurements of oxygen consumption rate be
affected?

If you have 10 ml of a culture of cells that has an absorbance of 0.5 A650 units,
what would its absorbance be if you brought its volume up to 50 ml with fresh
medium?