How does banking affect the money supply? in your own words

The bank will keep some of it on hand as required reserves, but it will loan the excess reserves out. When that loan is made, it increases the money supply. This is how banks “create” money and increase the money supply. When a bank makes loans out of excess reserves, the money supply increases.

Explanation:

the answer to your question is,

old stone age.

-mabel < 3