In general one or more attributes will contibute to the primary - but not necessarily all of them.
It is the other way around. Non-key attributes are determined by key attributes.
This is true for any relation in third normal form.
This is true for a relation in BCNF. A relation in 3rd normal form might not have this property.
A relation in 3rd normal form may also be in 4th normal form. However there are exceptional cases where a relation is in third normal form but NOT in 4th normal form.
A given relation is known to be in third normal form. Select the statement which can be inferred from this: