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GCSE Biology · key term
The stage of human development from about eight weeks after fertilisation until birth.
Used by AQA
Specification 4.2.2.6 · Paper 1
Revise: Effects of Lifestyle on Unborn BabiesA developing foetus needs oxygen and nutrients but cannot obtain them independently. The placenta, attached to the wall of the uterus and connected to the foetus by the umbilical cord, allows useful substances to pass from the pregnant person's blood towards the foetus. Waste substances such as carbon dioxide pass in the opposite direction.
For smoking, make the oxygen link explicit: carbon monoxide reaches the foetus, so it receives less oxygen for growth and development.
Keep the two mechanisms distinct: cigarette smoke reduces the foetus's oxygen supply, whereas alcohol can directly disrupt the development of the brain and other body parts.
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