Question

many people moved to california in 1848 following
the establishment of bear flag republic.
the outlawing of slavery.
the discovery of gold.
the completion of the pacific railroad.

Explanation:

In 1848, gold was discovered at Sutter's Mill in California, triggering the California Gold Rush, which led to a massive influx of people seeking fortune. The Bear Flag Republic was established in 1846, California outlawed slavery later in 1850, and the Pacific Railroad was completed in 1869, so these do not align with the 1848 timeline.

Answer:

the discovery of gold.