Antibiotics target bacterial infections only

Steps:

• Recall that antibiotics kill or inhibit bacteria but are ineffective against viruses or fungi.
• Identify disease 1 as viral (e.g., common cold), which cannot be treated with antibiotics.
• Identify disease 2 as viral (e.g., influenza), also unresponsive to antibiotics.
• Identify disease 3 as bacterial (e.g., strep throat), treatable with antibiotics like penicillin.

Why D is correct:

• Antibiotics work by disrupting bacterial cell walls or protein synthesis, as per their pharmacological definition, making them effective solely for bacterial disease 3.

Why the others are wrong:

• A includes viral diseases 1 and 2, which antibiotics cannot treat.
• B selects only viral disease 1, ineffective for antibiotics.
• C includes viral disease 2, which resists antibiotic treatment.

Final answer: D