Question

question 12
1 pts
an organism’s first line of defense against attack by a pathogen such as a virus or bacterium is usually
○ phagocytosis of the pathogen or one of the other innate immune responses.
○ inflammation at the entry site of the pathogen.
○ a barrier, like the skin of a vertebrate or the cuticle of a plant.
○ antibody production or one of the other adaptive immune responses.

Explanation:

To solve this, we analyze the immune system's defense lines:

• The first line of defense is physical/chemical barriers (e.g., skin, plant cuticle) that prevent pathogen entry.
• Phagocytosis and inflammation are part of the second (innate) line of defense.
• Antibody production is part of the third (adaptive) line of defense.

Thus, the correct option is the one describing a barrier.

Answer:

C. a barrier, like the skin of a vertebrate or the cuticle of a plant.