Question

chapter 25: endocrine and immune systems: testing the iceman
page(s) 498 503 25.3. identify the immune system’s first, second, and third lines of defense.
complete the following passage regarding the three main strategies of the immune system for fighting infection.
complete the passage by filling in the blank(s). drag the word(s) below to fill in the blank(s) or use your keyboard to choose word(s) from the dropdown menus.
the first line of defense includes defenses such as skin, mucus, and tears. the second line of defense involves the immune system, including such as neutrophils and macrophages. these responses are considered . the third line of defense includes responses such as the generation of antibodies and differentiation of into mature b cells and t cells.
lymphocytes nonspecific specific secondary innate phagocytes primary
chemical external physical macrophages

Explanation:

Step1: Fill first blank

First line defenses (skin, mucus, tears) are physical/chemical barriers.
Possible words: physical/chemical. Let’s assume the first blank takes "physical" (common primary term for skin/mucus/tears as barriers).

Step2: Fill second blank

Second line is innate immune system.
Word: innate.

Step3: Fill third blank

Neutrophils/macrophages are phagocytes.
Word: phagocytes.

Step4: Fill fourth blank

Innate responses are nonspecific.
Word: nonspecific.

Step5: Fill fifth blank

Third line is specific (adaptive) immunity.
Word: specific.

Step6: Fill sixth blank

B/T cells develop from lymphocytes.
Word: lymphocytes.

Answer:

The first line of defense includes physical defenses such as skin, mucus, and tears. The second line of defense involves the innate immune system, including phagocytes such as neutrophils and macrophages. These responses are considered nonspecific. The third line of defense includes specific responses such as the generation of antibodies and differentiation of lymphocytes into mature B cells and T cells.