The labels have been removed from two brain-scan records.
Record P is a sharp cross-sectional image showing the position of a small bleed.
Record Q is a colour-coded image showing that one brain region has lower activity than in a healthy person.
Which statement correctly interprets the records?
Record P could be either scan because both locate bleeds; record Q is a CT scan because activity changes X-ray absorption.
Record P is a PET scan because it gives sharper structural detail; record Q could be either scan because both measure activity.
Record P is a CT scan because it shows brain structure; record Q is a PET scan because it shows brain activity.
Both records are PET scans because a PET scan shows the structure of the brain and its activity in the same image.
111 exam-style questions on Edexcel GCSE Biology 2.3 The nervous system and brain, covering 2.3.1 Structures and functions of the brain, 2.3.2 Imaging brain function with scanning, 2.3.3 Limitations in treating nervous system damage, 2.3.4 Neurones and impulse transmission, and 2.3.5 Structure and function of a reflex arc. Each one has a worked solution and a mark scheme showing where the marks go.