Who can elaborate on why electrons flow from the earth to the conductor?

The earth is a good conductor. Because it is very large, it can accept a lot of charge without obviously changing the earth's potential, just like pumping water from the ocean.

Neither water nor releasing water into the ocean can significantly change the height of sea level. If the charged conductor is grounded with a wire, the charge will flow out of the charged body.

The earth, until the conductor is particularly charged, can be considered no longer charged. If the conductor is positively charged, in fact, free electrons flow from the earth to the conductor. therefore

Effective for positive charge flowing from conductor to earth. )