The main difference between antibiotics, antiseptics and disinfectants is their mode of action, the type of microorganisms they target, their chemical composition and how they are applied.

Step 1: Identifying the main difference between antibiotics, antiseptics, and disinfectants
Antibiotics, antiseptics, and disinfectants all have different ways in which they work. Antibiotics are used to treat bacterial infections by interfering with the ability of bacteria to grow and multiply. Antiseptics are applied to the skin or mucous membranes to kill microorganisms or prevent infections. Disinfectants are used to kill or inactivate microorganisms on non-living surfaces.

Step 2: Explaining the type of microorganisms targeted by each of the agents
Antibiotics specifically target bacteria and are designed to kill or inhibit the growth of bacterial pathogens. Antiseptics are used against microorganisms such as viruses, fungi, and bacteria, which can cause infections. Disinfectants target pathogens that may be present on non-living surfaces, such as bacteria, viruses, and fungi.

Step 3: Comparing the chemical composition of the agents
Antibiotics are typically derived from natural sources or synthesized from chemical compounds, while antiseptics and disinfectants are chemically engineered to specifically target specific microorganisms. Antibiotics are typically administered orally or injected, while antiseptics and disinfectants are applied topically or by surface application.

Step 4: Describing how antibiotics, antiseptics, and disinfectants are applied
Antibiotics are prescribed by a healthcare professional and are administered orally or by injection to treat bacterial infections. Antiseptics are used topically on the skin or mucous membranes to prevent infections. Disinfectants are used on non-living surfaces to kill microorganisms.