Question

what is a key characteristic of anorexia nervosa?
eating large amounts of food in one sitting
food restriction and extreme fear of gaining weight
feeling unconcerned about body image
purging food after eating to maintain weight

Explanation:

Anorexia nervosa is an eating disorder characterized by self - imposed food restriction and an extreme, irrational fear of gaining weight. "Eating large amounts of food in one sitting" is a characteristic of binge - eating disorder. "Feeling unconcerned about body image" is not related to anorexia nervosa as those with anorexia are very concerned about body image. "Purging food after eating to maintain weight" is a characteristic of bulimia nervosa. So the key characteristic of anorexia nervosa is food restriction and extreme fear of gaining weight.

Answer:

food restriction and extreme fear of gaining weight