During the california gold rush, about 25,000 laborers migrated to california from

China

Explanation:

Early in 1849 the news of the gold fever was already known all over the world, and a huge amount of gold researchers and dealers began arriving from almost every continent.

Those who came from Asia, especially from China, began to arrive in 1849, initially in small numbers. In Chinese, California was called the "Golden Mountain."

wealthy plebeians became part of the roman nobility. however, despite changes in the laws, the patricians always held a majority of the wealth and power in ancient rome. a third social class in roman society was the slaves. around one third of the people living in rome were slaves.

hope this

radioactive dating, also known as  radioisotope dating  is a process that in  estimating the approximate  age  of  rocks. these data can be analyzed from  the studies dealing with the  decay of the radioactive elements that are present in these rocks. in nature, there are a few types of materials or atoms which are quite unstable and they spontaneously decay or breakdown to form other kinds of atoms.