Which of the following best completes the statement: A pathogen is a microbe whose relationship with its host is _____ and results in infection and _____?

• A. commensal; health
• B. mutualistic; immunity
• C. parasitic; disease
• D. symbiotic; nutrition

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the key terms in the statement. A pathogen is a microbe that interacts with a host in a way that causes harm, so the relationship is not neutral or beneficial.
2. Step 2: Review the types of relationships between microbes and hosts: commensal (one benefits, other unaffected), mutualistic (both benefit), parasitic (one benefits at the expense of the other), and symbiotic (close association, can be mutualistic or parasitic).
3. Step 3: Recognize that infection implies the microbe is causing harm or disease to the host, which aligns with a parasitic relationship where the microbe benefits and the host is harmed.
4. Step 4: Match the terms to the blanks: the relationship is 'parasitic' because the pathogen harms the host, and the result is 'disease' because infection leads to illness.
5. Step 5: Conclude that the best completion of the statement is: 'A pathogen is a microbe whose relationship with its host is parasitic and results in infection and disease.'