A student walks from a dim room into bright sunlight. Light reaches the retina, and the student's pupils become smaller without the student deciding to change them.
Which statement explains why the pupils become smaller?
It is controlled by the brain and protects the retina from damage
It is controlled by the spinal cord and allows more light to reach the retina
It is controlled by the spinal cord and protects the retina from damage
It is controlled by the brain and allows more light to reach the retina
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.