Simple categories matching viable:

• pathogen,
• vitamin,
• microorganism,
• entity,
• agent,
• cell,
• fungus,
• microbe,
• organism,

Members with property viable:

• pollen_grain,
• virus,
• thiamine,
• bacteria,
• hybrid,
• fungi,
• hiv,
• acidophilus,
• influenza_virus,
• bacterium,
• mycobacterium,
• niacin,
• rickettsia,
• parasite,
• yeast,
• photosynthetic_bacteria,
• mutant,
• fungus,
• vegetative_bacteria,
• amoeba,
• salmonella,
• algae,
• recombinant,