") popup.document.write(s1+s2+s3) } function popA(){ PopIt('A', 'Blastula') } function popB(){ PopIt('B', '2-celled embryo') } function popC(){ PopIt('C', 'Unfertilized egg') } function popD(){ PopIt('D', 'Fertilized egg') } function popE(){ PopIt('E', 'Late cleavage') } function popF(){ PopIt('F', 'Bipinnaria larva') } function popG(){ PopIt('G', 'Gatrula') } function popH(){ PopIt('H', '8-celled embryo') } function popI(){ PopIt('I', 'Early gastrula') }