Biology · May / June 2020 · Paper 11 · Question 20

Which of these statements describes control by negative feedback?

1. AAn injury to body tissue activates platelets in the blood and these activated platelets release chemicals which activate more platelets.
2. BDuring the menstrual cycle, luteinising hormone (LH) stimulates the release of oestrogen which in turn stimulates the release of more LH.
3. CA higher concentration of carbon dioxide in the atmosphere increases temperature, which increases photosynthesis producing more carbon dioxide.
4. DWhen blood pressure is high, nerve impulses from the brain cause the blood vessels to dilate and blood pressure is reduced.

As printed in the paper