In relation to kidney function, infer why a doctor would ask you to take an antibiotic such as
penicillin for several days rather than in one single
dose.

an active site is a region that is present on an enzyme where the reactants or the substrate molecules we can say bind and experience a chemical reaction. the substrate is basically a reactant whose concentration is changing and that is converting into a product after binding at the active site of an enzyme

b is the answer and if you need further with anything message me

answer: b

coz red blood cells marrow and circulates the body for 120 days.