Final answer:
The West Wind in Shelley's poem is called a 'destroyer and preserver' due to its dual role in ending one cycle and laying the groundwork for new life, reflecting the natural progression from death to regeneration.
Step-by-step explanation:
In the poem Ode to the West Wind by Percy Bysshe Shelley, the West Wind is described as both a destroyer and preserver because of its dual nature in bringing about change and renewal. As a destroyer, the wind drives the last signs of life from the trees in Autumn, signifying the end of a cycle. However, it also scatters the seeds that will lie dormant through the winter and sprout in the spring, thus preserving the promise of future growth and regeneration. This juxtaposition highlights the wind's role in the natural cycle of death leading to life.