Final answer:
President James Polk's address to Congress applies to the effects of the Westward Expansion on California's gold through the events surrounding the California Gold Rush in 1848.
Step-by-step explanation:
President James Polk's address to Congress applies to the effects of the Westward Expansion on California's gold through the events surrounding the California Gold Rush in 1848. The discovery of gold in California led to a population boom, attracting people from all over the country to seek their fortune.
The rapid growth in population prompted California to consider applying for statehood, which had implications for the extension of slavery. President Polk's response to this situation was to encourage the creation of a state constitutional convention in California, with the aim of skipping the creation of a territory and moving directly to the application for statehood.