KaKaKa

parent(queenmother,elisabeth).
parent(elisabeth,charles).
parent(elisabeth,andrew).
parent(elisabeth,anne).
parent(elisabeth,edward).
parent(diana,william).
parent(diana,harry).
parent(sarah,beatrice).
parent(anne,peter).
parent(anne,zara).
parent(george,elisabeth).
parent(philip,charles).
parent(philip,andrew).
parent(philip,edward).
parent(charles,william).
parent(charles,harry).
parent(andrew,beatrice).
parent(andrew,eugenie).
parent(mark,peter).
parent(mark,zara).
parent(william,georgejun).
parent(kate,georgejun).
parent(william,charlotte).
parent(kate,charlotte).
parent(philip,anne).
parent(william,louis).
parent(kate,louis).

%1.a.
the_royal_females([queenmother, elisabeth, anne, diana, sarah, beatrice, zara, eugenie, kate, charlotte]).

%1.b.
the_royal_males([charles, andrew, edward, william, harry, peter, george, philip, mark, george, louis]).

%2
the_royal_family(X) :- the_royal_females(XF), the_royal_males(XM), append(XF, XM, X).

%3
mother(X,Y) :- parent(X,Y), the_royal_females(XF), member(X, XF).

%5
sibling(X,Y) :- parent(A,X), parent(A,Y).

%6
brother(X,Y) :- the_royal_males(XM), (member(X, XM), sibling(X,Y).