申論題

 Although mutations do occur naturally in organisms over the course of many generations, research has shown that environmental factors—radiations and chemicals—increase the rates and types of mutations. A prime example of this is the enormous increase in animal deformations in areas surrounding the Chernobyl nuclear plant. Since the accident, 197 deformed calves and about 200 abnormal piglets have been born. The severity of these deformities is frightening, including animals with no eyes, deformed skulls, and distorted mouths.