Answer:
least, most
Step-by-step explanation:
Antimicrobials are substances that function by limiting the activities of microorganisms either by killing them or by inhibiting their growths.
Antimicrobials that exhibit a wide range of cellular targets are least selective of the type of cells they kill or inhibit. They are also said to have a wide spectrum of activities.
On the other hand, antimicrobials that exhibit a narrow range of cellular targets are most selective of the type of cells they kill or inhibit. They are said to have a narrow spectrum of activities.