Final answer:
The wind's effect in the first three stanzas of "Ode to the West Wind" is on leaves, waves, and clouds.
Step-by-step explanation:
The first three stanzas of "Ode to the West Wind" describe the wind's effect on leaves, waves, and clouds. In the poem, the wind is portrayed as having a powerful and transformative impact on these elements of nature. The leaves are described as trembling and turning like the approach of a breeze on the water. The waves are depicted as scallop-edged and the clouds as purple and black, rolling swiftly and low across the valley.