Question

1. which statement best describes how white blood cells fight viral infections

a. they release chemicals that break viruses apart instantly
b. they surround, engulf, and digest pathogens
c. they weaken their own membranes during infection
d. they allow viruses to reproduce inside them

1. identify one trade - off of receiving an annual covid - 19 vaccine.

Explanation:

Question 4

• Option A: White blood cells don't release chemicals to break viruses apart instantly; this is not accurate.
• Option B: Phagocytic white blood cells (like macrophages, neutrophils) surround, engulf (phagocytose), and digest pathogens (including viruses - though viruses need to be inside host cells first, but the process of dealing with pathogens includes this for extracellular ones or after cell lysis), so this is a correct mechanism.
• Option C: White blood cells don't weaken their own membranes during infection; this is incorrect.
• Option D: White blood cells do not allow viruses to reproduce inside them; viruses infect host cells (not white blood cells in a way that they allow reproduction for fighting; some white blood cells can be infected but that's not part of their defense mechanism), so this is incorrect.

A trade - off is giving up something to gain something else. For the annual COVID - 19 vaccine, one trade - off could be the time spent getting the vaccine (e.g., taking time off work or other activities to go to the vaccination site) in exchange for reduced risk of severe COVID - 19 illness. Another could be the potential minor side effects (like soreness at the injection site, mild fever) in exchange for protection against the virus.

Answer:

B. They surround, engulf, and digest pathogens

Question 5