DP Biology (first assessment 2025)
Question 19M.1A.SL.TZ2.36
| Date | May 2019 | Marks available | [Maximum mark: 1] | Reference code | 19M.1A.SL.TZ2.36 |
| Level | SL | Paper | 1A | Time zone | TZ2 |
| Command term | Deduce | Question number | 36 | Adapted from | N/A |
36.
[Maximum mark: 1]
19M.1A.SL.TZ2.36
The blood of two men was tested and the results are shown. Anti-D refers to the rhesus blood group. Clotting indicates that antigens associated with a particular factor or blood group are present in a blood sample.
[Source: © International Baccalaureate Organization 2019]
The man who tested positive for anti-D was then tested for ABO blood group. These results were obtained.
[Source: © International Baccalaureate Organization 2019]
What ABO blood group does the man testing positive for anti-D have?
A. A
B. B
C. AB
D. O
[1]
Markscheme
D
Examiners report
Many candidates failed to realize that a negative reaction meant the antigens for A and for B were not present in the blood of the man tested.
