DP Biology (first assessment 2025)

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Question 23M.2.SL.TZ2.e

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Date May 2023 Marks available [Maximum mark: 2] Reference code 23M.2.SL.TZ2.e
Level SL Paper 2 Time zone TZ2
Command term Suggest Question number e Adapted from N/A
e.
[Maximum mark: 2]
23M.2.SL.TZ2.e

Suggest reasons for the difference between the data for S. pneumoniae and H. influenzae.

[2]

Markscheme
  1. Hib vaccination program started earlier/PCV vaccination program started later
    OR
    Hib vaccine developed before PCV vaccine;
  2. deaths due to H. influenzae drop earlier than deaths due to S. pneumoniae because of earlier vaccination;
  3. more deaths due to S. pneumoniae than H. influenzae (in any year) as lower % of children vaccinated against S. pneumoniae (compared H. influenzae);

Mp a to c: accept vice versa.

Comparative terms expected (do not award mp for just stating values).

Mpa and mpb: there must be a clear reference to time.

Mpc: there must be clear indication to vaccination.

Allow no points for bacterial virulence / disease severity, etc., as bacterial pathogenicity is not addressed on graphs.

Syllabus sections