Which option is NOT one of the four routes of entry into the body?

• A. Inhalation
• B. Ingestion
• C. Absorption
• D. Excretion

Answer: (D)

Excretion is the process by which the body removes substances it has already taken in, through means like urine, feces, sweat, or breath. The ways a substance can enter the body are inhalation (through the lungs), ingestion (through the mouth and digestive tract), absorption (through the skin or mucous membranes), and injection (entry via a puncture or needle). Since excretion involves elimination after exposure, it does not describe a route for something to enter the body. That’s why excretion is not a route of entry.