Respuesta :
Answer: D) Selective pressures by excessive antibiotic use have increased the frequency of resistant strains of S. aureus over the last few decades.
Explanation: Excessive use of antibiotic have lead to increased resistance of strains of S. aureus over the last few decades. The consistent use of antibiotics without proper test and prescriptions have lead to strains of S. aureus becoming more resistant.
The microorganism develops a means to resist the effects of the antibiotics. This methods may include secretion of substances that deactivates the antibiotics over time, modification of cells to resist specific target organs.
Therefore it is advised that proper test should be carried out and the correct prescription / dosage taken.