A nerve bundle in the arm contains many axons carrying impulses to different muscles. One axon is wrapped in a fatty layer broken by regular gaps.
Which statement describes how this layer helps the nerve to work?
It stores fat for respiration, so the axon has enough energy to carry impulses
It forms a synapse at each gap, so impulses can pass between neighbouring axons
It joins neighbouring axons together, so one impulse can stimulate all of the muscles at once
It stops impulses crossing between neighbouring axons, so each muscle receives only its own signals
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.