Final answer:
A completely life-free environment is referred to as sterile (option A) . Sterilization removes all life forms including spores and virus particles, and is done using methods like heat or chemicals called sterilants. Antiseptics are used on tissues for microbial control to prevent infection.
Step-by-step explanation:
An environment or material that is completely free of all life forms, including spores and virus particles, is referred to as sterile. Sterilization is a protocol that completely removes all vegetative cells, endospores, and viruses from an item. This process uses either physical means, such as heat or pressure, or chemical means known as sterilants. In clinical settings, aseptic technique is used to maintain sterility and prevent contamination during medical procedures.
For microbial control on tissues to prevent infection, antiseptics are suitable because they are antimicrobial chemicals safe enough for living tissues. Disinfection, on the other hand, reduces the microbial load on fomites but does not guarantee sterility, as it may not eliminate all microbes, particularly endospores.