A fertility service reviews the outcomes of 250 IVF cycles. In each cycle, one embryo was transferred into the uterus.
| Outcome after transfer | Number of cycles |
|---|---|
| Pregnancy began | 90 |
| Pregnancy did not begin | 160 |
Which option gives the percentage of transferred embryos known to have implanted and the reason this is known?
56%; a pregnancy begins only if the embryo implants in the uterus lining
36%; a pregnancy begins only if an egg is released from an ovary after transfer
56%; a pregnancy begins only if an egg is released from an ovary after transfer
36%; a pregnancy begins only if the embryo implants in the uterus lining
90 exam-style questions on Edexcel GCSE Biology 7.2 Reproductive hormones, covering 7.2.1 Stages of the menstrual cycle, 7.2.2 Hormonal control of the menstrual cycle, 7.2.3 Hormonal contraception, 7.2.4 Evaluating contraception methods, and 7.2.5 Hormones in Assisted Reproductive Technology. Each one has a worked solution and a mark scheme showing where the marks go.