Final answer:
The statement that the erythrocytes of birds and amphibians are nucleated is true. Mammalian erythrocytes are the exception as they eject their nuclei during maturation. Bird and amphibian red blood cells retain their nuclei, allowing for certain metabolic activities.
Step-by-step explanation:
The erythrocytes, or red blood cells, of birds and amphibians are indeed nucleated. This statement is True. Unlike mammalian red blood cells which lack nuclei at maturity, the erythrocytes of birds and amphibians contain nuclei. Mammalian erythrocytes are unique in this aspect as they eject their nucleus during maturation to optimize space for hemoglobin, which is essential for oxygen transport. The presence of nuclei in bird and amphibian erythrocytes means that these cells can engage in protein synthesis and metabolic activities that mammalian red blood cells cannot perform due to the absence of a nucleus.