Accounting originated when the first trading started back at 3000BC. It used to keep all exchange information in a book.
Inventory refers to the goods stocked for future usage. Every retail chain has its own warehouse to stock the merchandise to be used when the existing stock replenishes.
Accounts payable occurred when a company procured some goods or raw materials from a seller on credit. So, on credit means the company opts for late payment within a stated duration.