The correct answers are:
Distinction: Nuance.
In this sentence, the distinction mentioned refers to differences between the bacteria, therefore the world "nuance" -which means a small difference in sound, feeling, appearance, or meaning- has the closest meaning.
Old-fashioned: Quaint.
"Quaint" is used to describe things that are attractive because they are unusual, specially when they are old-fashion.
Preference: Inclination
"Preference" here refers to liking something or someone more than others. At the same time, having an "inclination" means to favour one above others.
Condemn: Denounce.
Both "condemn" and "denounce" mean to crticize strongly and publicly.
