Question

Five jumbled up sentences (labelled 1, 2, 3, 4 and 5), related to a topic, are given below. Four of them can be put together to form a coherent paragraph. Identify the odd sentence and key in the number of that sentence as your answer.

• A. To create a synapse, the neuron has specialized structures, often seen as tiny swellings, at its terminal end of the axon where it stores the chemicals that are emitted to transmit a signal to the next neuron.
• B. This fetal warm-up act—the soldering of neural connections before the eyes actually function—is crucial to the performance of the visual system.
• C. The reasons for this paring back of synapses is a mystery, but synaptic pruning is thought to sharpen and reinforce the “correct” synapses, while removing the weak and unnecessary ones.
• D. Neural connections between the eyes and the brain are formed long before birth, establishing the wiring and the circuitry that allow a child to begin visualizing the world the minute she emerges from the womb.
• E. During this rehearsal period, synapses—points of chemical connection—between nerve cells are generated in great excess, only to be pruned back during later development.