| Date | May 2011 | Marks available | 1 | Reference code | 11M.1.HL.TZ1.40 |
| Level | Higher level | Paper | Paper 1 | Time zone | Time zone 1 |
| Command term | Question number | 40 | Adapted from | N/A |
Question
Which of these statements about the human placenta is incorrect?
A. The placenta is the site of nutrient and gas exchange between the mother and fetus.
B. The placenta produces hormones, such as estrogen.
C. The placenta begins to develop after implantation of the blastocyst.
D. The mother’s blood and the baby’s blood mix in the placenta.
Markscheme
D
Examiners report
While D was obviously the correct response as the mother‟s blood and baby‟s blood do not mix in the placenta, many were distracted by the B. In 11.4.12, the secretion of both estrogen and progesterone by the placenta is to be included.
