What is the goal of invading bacteria and viruses in relation to the human body?

• A. use a human body as a home
• B. kill their human host
• C. cause an immune response
• D. spread disease and destruction

Answer: (A)

Pathogens invade to use the human body as a home where they can live, access nutrients, and reproduce. The body provides a stable environment and resources for growth, and by reproducing inside the host they gain more opportunities to spread to new hosts. Killing the host quickly would limit those opportunities, so many invaders are adapted to coexist for a period while they replicate. An immune response is what happens when the body detects the invaders; it’s a consequence of invasion, not the invader’s goal. Destruction of tissue and spread can occur, but the fundamental aim is to exploit the body's resources and environment to replicate and survive, which is best captured by using the body as a home.