DP Biology (last assessment 2024)

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Question 23M.2.HL.TZ1.a

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Date May 2023 Marks available [Maximum mark: 2] Reference code 23M.2.HL.TZ1.a
Level HL Paper 2 Time zone TZ1
Command term Explain Question number a Adapted from N/A
a.
[Maximum mark: 2]
23M.2.HL.TZ1.a

Explain the conclusion that can be drawn from Cross 1.

[2]

Markscheme
  1. allele/trait/gene for banded is dominant/allele for unbanded is recessive;
  2. because two banded spiders produced some unbanded offspring
    OR
    because there is a ratio of 3 banded:1 unbanded;
  3. both parents are heterozygous;

Accept answers given in the form of Punnet squares.

 

Examiners report

SL:

Candidates were moderately successful at answering (a) and (c), but unsuccessful at (b) and (d). In many responses, some understanding was indicated, but the words needed to express the answer were lacking. 

HL:

This was relatively well answered, with many candidates scoring both marks.

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