female(shelley). female(mary). male(jake). male(bill). father(bill, jake). father(bill, shelley). mother(mary, jake). mother(mary, shelly). parent(X, Y):- mother(X, Y). parent(X, Y):- father(X, Y). grandparent(X, Z):- parent(X,Y), parent(Y, Z). sibling(X, Y):- parent(P, X), parent(P,Y). /* Try the following queries seperately. sibling(shelly, jake). mother(shelly, jake). parent(X, jake). sibling(X, jake). */