[문 16～문 18] It is ㉠ to give reliable general rules for the validity of extrapolation from one species to another. This can often only be verified after the first trials in the target species (humans). Extrapolation from animal models will always remain a matter of hindsight. ㉡ the results of animal tests can be dangerously misleading and has cost the health and lives of tens of thousands of humans. ㉠ ㉡