A firm's are best described as distinct and fine-grained business processes such as order taking, physical delivery of products, or invoicing customers.

Activities.

Explanation:

A firm's activities are the various business processes that a firm engages in with the aim of making profit or meeting other organisational goals.

They are distinct and well defined processes that have laid down prcedures and policy for execution. For example when a business is replying to the order of a client for a product there are laid down guides on how to go about this. From the expected turn around time to the steps in fulfilling the order.

These policies make a business's processes unique.

turnover

the amount of money taken by a business in a particular period.

answer/// equals both average variable cost and average total cost at their respective minimums;