rule(mammal(X), [gives_milk(X)]).
rule(mammal(X), [has_hair(X)]).

rule(ungulate(X), [mammal(X), chews_cud(X)]).

rule(giraffe(X), [ungulate(X), has_long_neck(X)]).

rule(zebra(X), [ungulate(X), has_black_and_white_stripes(X)]).

askable(gives_milk(X)).
askable(has_hair(X)).
askable(chews_cud(X)).
askable(has_long_neck(X)).
askable(has_black_and_white_stripes(X)).
askable(mammal(X)).