Question

lo 6.4. what does the chemical examination of urine involve?
testing for the presence of certain substances, such as glucose, protein, and blood.
looking for the presence of bacteria and viruses in the urine.
testing for the presence of certain substances, such as calcium, sodium, and potassium.
testing the urines ph level and acidity.
checking for the presence of electrolytes, such as magnesium and chloride.

Explanation:

Chemical examination of urine typically involves testing for substances like glucose (indicative of diabetes if present in excess), protein (can suggest kidney issues), and blood (may point to infections, kidney problems, or other pathologies). Bacteria and viruses detection is more of a microbiological aspect. Testing for calcium, sodium, potassium, pH, and electrolytes like magnesium and chloride are more related to specific biochemical or electrolyte - balance tests rather than the core chemical examination which often first looks at glucose, protein, and blood as key markers.

Answer:

Testing for the presence of certain substances, such as glucose, protein, and blood.