Final answer:
The red blood cells of birds, reptiles, and amphibians are nucleated, unlike those in mammals.
Step-by-step explanation:
The red blood cells of birds, reptiles, and amphibians differ from those in mammals in that they are nucleated. This means that they contain a nucleus, unlike the red blood cells of mammals, which lack a nucleus. This difference allows for greater flexibility and adaptability of the red blood cells in birds, reptiles, and amphibians.
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