The booklet is part of a series which tests some skills biologists use in their investigations. A series of drawings of the inhabitants of two fictional villages, and a number of extracts of literature concerning congenital malformations, introduce the first question in this test, which asks students to identify an unusual event shown in the illustrations. Students are presented with a choice of procedures to investigate the problem they choose, and a scrambled program text format is used to direct them to related questions. Some of the choices direct students to extracts of literature, upon which further questions are based. Students are allowed 55 minutes to complete this booklet. Booklet B (SE 011 339) asks students a series of questions about one possible explanation for the puzzling event. (AL)