Question

1. step 3: critical thinking

if my first line of defense (the ______ system) failed completely, then ______.
the reason multiple body systems work together instead of having one super-immune system is probably because

Explanation:

1. For the first blank: The body's first line of defense is the innate (nonspecific) immune system (includes physical/chemical barriers like skin, mucus).
2. For the second blank: If the innate system fails, the adaptive (specific) immune system (with B cells, T cells, antibodies) would activate to target specific pathogens.
3. For the reasoning: Multiple systems work together for redundancy, specialization, and efficiency—different threats require different responses, and layered defenses (innate → adaptive) increase survival odds (e.g., innate stops most threats; adaptive targets evaders).

Answer:

• First blank: Innate (Nonspecific)
• Second blank: The adaptive (specific) immune system would activate to target the pathogen(s).
• Reason: Multiple systems provide redundancy, specialization, and layered defense (innate blocks most threats; adaptive targets evaders), increasing the body’s ability to survive diverse infections.