Respuesta :
I think the answer is d because the bodys first line of defense is both physical and chemical barriers ect. skin, tears, mucus, cilia, stomach acid and urine flow
Skin is the body's first line of defense against infection.
- It serves as a barrier to any type of dust, germs and other invading organisms.
What is a first line of defense?
- The first line of defense include physical and chemical barriers that are always ready and prepared to defend the body from infection.
- These include skin, tears, mucus, cilia.
To know more about body defense here
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