Describe what happens, at a microscopic level, when an object is charged by rubbing. for instance, what happens when a plastic pipe is rubbed with a cloth? describe the specific case where the rod becomes negatively charged

Explanation:

The static charges are generated due to excess or deficiency of electrons, because these are the smallest quanta of charge available at the molecular level which can get transferred with minimal energy requirement.

These charges are usually generated by friction between  the two surfaces leading to the transfer of electron from one to another.

When a plastic pipe is rubbed with a cloth then due to friction the surface of the cloth loses electron which gets stuck at the surface of the pipe making it negatively charged.

i would think it's food chain

this is a good question! i'll do some research and come back when i have the answer!