“Firms in the market produce homogeneous products that are perfect substitutes for each other.

There is perfect knowledge – consumers have perfect information about prices and products so can switch.

Each firm produces only a small percentage of total market output and exercises no control over the market price.

No individual buyer has any control over the market price.

There is perfect freedom of entry and exit from the industry

There are no externalities which lie outside the market”

As you can tell it is a theoretical construct used to enlighten economic thought on what a market is, not a comment on reality.

www.tutor2u.net will cover all these pre-18 questions to a skim-level which is useful before class and to catch up on missed work.