Final answer:
Bacteriophages for treatment purposes are stored in laboratories in a solution or suspension, usually in a cold environment.
Step-by-step explanation:
Phage therapy is a procedure that uses bacteriophages, or bacteria-killing viruses, to treat bacterial infections. Bacteriophages are stored in laboratories for treatment purposes by preserving them in a solution or suspension, usually in a cold environment such as a refrigerator or freezer. This helps to maintain the viability and effectiveness of the bacteriophages until they are needed for treatment.