Final answer:
The discovery of gold in California during the 1848 Gold Rush caused San Francisco's population to grow rapidly from about 500 to almost 100,000 by 1853.
Step-by-step explanation:
The discovery of gold in California in 1848 had a profound impact on the population of San Francisco. The news of gold spread quickly, attracting a large influx of people to the region in search of fortune. By 1853, San Francisco's population had grown from about 500 to almost 100,000. This rapid growth was a result of the California Gold Rush and the desire for quick riches.