cracks in the same person on the periodic desk of pairs have similar northward
one_quintillionth is common_fraction. cracking is chemical_process. cracking is separating. tetrad is homologous_chromosome_pair. perulactone is withanolide. ixocarpalactone is withanolide. fault is crack. cracking_reaction is chemical_decomposition. parallel_axiom is euclid's_postulate. toe_crack is sand_crack.