A $30-mL$ biodegradable organic waste sample is diluted with seeded dilution water and placed into $300-mL$ stoppered BOD bottle $($no headspace$).$ The dissolved oxygen data from the BOD bottle are as follows $($see table$).$

a$.$ Calculate $BO{D}_t$ for each time point. Show an example calculation for day $1.$

b$.$ At which time point $(0-7$ days$),$ is the concentration of organic matter in the BOD bottle the highest, and at which point is it the lowest?

c$.$ Why is the dissolved oxygen concentration decreasing in the BOD bottle over time?

$\backslash$table$[[$Time $($d$),\backslash$table$[[$Dissolved oxygen$],[($diluted sample, $m\frac{g}{L}$