Final answer:
The correct option is a. Glucose is not a normal constituent of urine; its presence can indicate diseases like diabetes mellitus. Normal urine primarily consists of water, urea, creatinine, and various ions.
Step-by-step explanation:
The constituent of urine that is NOT normally present is glucose. Urine mainly consists of water but also contains nitrogenous waste such as urea, along with creatinine and ions like sodium.
The presence of glucose in the urine may indicate a condition like diabetes mellitus due to the inability of the kidneys to reabsorb all glucose back into the bloodstream. Glucose is not a normal constituent of urine; its presence can indicate diseases like diabetes mellitus. Normal urine primarily consists of water, urea, creatinine, and various ions.