Final answer:
Prosauropods are believed to be plant-eaters based on their long necks, teeth adapted for eating plants, and body structures suited for grazing, as evidenced by their fossils.
Step-by-step explanation:
The anatomical evidence that supports the notion that prosauropods were plant-eaters comes from the distinct features of their fossils. One strong indicator is the presence of long necks which would have allowed them to reach vegetation at various heights. Additionally, their teeth were adapted for a herbivorous diet, being shaped to strip, snip, and chew plant materials. The prosauropods' body structure, including their limb and torso configuration, suggests they were adapted to a grazing lifestyle to consume large amounts of vegetation. While these dinosuars are extinct today, their fossilized remains provide invaluable information for understanding their ecology and dietary habits.