We don't see a crop and gizzard in many vertebrates; why do we see them in most birds?

Question

Quizplus · Accepted Answer

Birds lack hands and teeth to reduce the size of their food, and they need to gather food quickly to avoid predators and competition. The crop and gizzard allow birds to quickly ingest and store food and then grind and break it down for digestion. These structures are not necessary for all vertebrates, but they are beneficial for birds with their unique feeding habits.

We Don't See a Crop and Gizzard in Many Vertebrates;