:-. It has the form of a comma-separated list of goals, each of which is a the name part of a functor, possibly followed by a comma-separated list of arguments, in parentheses. E.g. in the rule
the three goals
sister_of(X,Y) :- female(Y), X \== Y, same_parents(X,Y).
female(Y), X \== Y, same_parents(X,Y)form the body.