Final answer:
The topic most clearly explored in 'Apostrophe to the Ocean' is 1) nature. Wordsworth capitalizes words like 'Nature' and 'Sea' to personify them and signify their importance and power.
Step-by-step explanation:
The topic most clearly explored in Apostrophe to the Ocean is 1) nature. This poem is known for its reflection on the power and beauty of the natural world, exemplified by the vast and untamed ocean.
The ocean serves as a symbol for the broader concept of nature's majesty and its enduring, unchangeable character, contrasting sharply with human frailties and societies that rise and fall.
Regarding Wordsworth and his use of capitalization, he often capitalized words like Nature and Sea to personify them and treat them as dignified entities.
This act signifies respect and acknowledges their powerful presence in the world, almost as if they were characters in their own right.
Other words capitalized in poems could relate to these two by being other elements of the natural world or concepts that are important within the context of the poem.