A Levels Biology (9700)•9700/13/M/J/21

Explanation
Identifying immune cell roles in viral response
Steps:
- Recall viral infection activates T-helper cells to stimulate B cells.
- B cells differentiate into plasma cells for antibody production and B-memory cells for immunity.
- T-memory cells provide long-term T-cell response, while T-killer cells target infected cells.
- Match labels: E as B-memory (long-term B immunity), F as T-helper (activation), H as plasma cell (antibody secretion).
Why A is correct:
- Option A aligns with standard humoral immunity: T-helper cells activate B cells to form plasma cells (antibody producers) and B-memory cells (per definition in adaptive immunity).
Why the others are wrong:
- B: Confuses T-helper with T-memory; T-memory forms after activation, not as primary activator.
- C: T-plasma cells do not exist; plasma cells are B-cell derived only.
- D: T-killer cells destroy infected cells but do not directly label as F (T-helper role).
Final answer: A
Topic: The immune system
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