Read the passage carefully and select the best answer to each question out of the given four alternatives.
Malnutrition affects millions of people worldwide and is responsible for one-fifth of deaths in children under the age of five. Children can also experience impaired cognitive development and stunted growth.
According to Finlay and UBC PhD student Eric Brown, malnutrition can be difficult to treat because it affects the good bacteria that live in the gut. People suffering from malnutrition often show signs of a disease known as environmental enteropathy, which is an inflammatory disorder of the small intestine and is likely caused by ingesting pathogenic fecal bacteria early in life from a contaminated environment. ................ ''People suffering from malnutrition respond differently.''
With an animal model, Finlay said researchers will be better able to test treatments and understand how malnutrition impacts a child's development.
Why malnutrition is difficult to be treated?