DP Biology (first assessment 2025)

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Question 22M.2.SL.TZ1.j

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Date May 2022 Marks available [Maximum mark: 2] Reference code 22M.2.SL.TZ1.j
Level SL Paper 2 Time zone TZ1
Command term Evaluate Question number j Adapted from N/A
j.
[Maximum mark: 2]
22M.2.SL.TZ1.j

A hypothesis has been proposed that an increase in parathyroid hormone concentration causes an increase in osteocalcin in bears. Evaluate the evidence for this hypothesis provided by the data.

[2]

Markscheme
  1. (hypothesis supported by)
    positive/direct correlation/direct relationship (between parathyroid hormone and osteocalcin)
    OR
    osteocalcin rises as parathyroid hormone rises/vice versa;
  2. no evidence for causal link / causal link cannot be assumed / correlation does not prove causation;
    OR
    no evidence that parathyroid hormone causes change in osteocalcin;
    OR
    other factors may cause change in osteocalcin;
Examiners report

This type of question is increasingly well answered with more candidates understanding that two variables being positively correlated does not prove a causation. The situation would have been different if an experiment had been done with the levels of parathyroid hormone as the independent variable controlled by the researchers.

Syllabus sections