A model organism is a species that has been widely studied to understand a particular biological phenomena, normally used because they are easy to breed and maintain in a laboratory setting and has certain experimental advantage.
The criteria that Thomas hunt Morgan was looking for include; the model organism should be small in size, easy to keep in the laboratory and also able to produce large number of off springs in a short time.
Overall, minerals from animal products are better absorbed than those from plant because binders such as fiber are not present to hinder absorption.
<span>The answer would be: a. inflammation is accompanied by an increase in peristaltic movements of his small intestine.
The pathogen will attract the white blood cells that will induce inflammation in the intestine. Inflammation of the intestine will cause increased permeability and increased bowel movement, makes the food transit time reduced and lead to diarrhoea. This mechanism is beneficial since it can help the intestine to "flush out" pathogen of toxins that induce the inflammation.</span>