If im reading it right and remember they are
rivalry among competing firms,
potential entry of new competitors,
potential development of substitute products,
bargaining power of suppliers,
and bargaining powers of consumers
There are a total of 535 members of Congress. There are 435 members in the House of Representatives which may or may not be what you teacher is referring to. There are 100 senators who sometimes count as congressman. Whether the answer is 535 or 453 is your decision, based on what you are learning in class at the moment.