name one animal cell and one plant cell that has no nucleus when fully developed. for each cell named, state its function

In animal cells, red blood cells do not have a nucleus when they are fully developed. The function of the red blood cells is to supply oxygen from the heart to every part of the body and carry carbon dioxide from the body parts backs to the lungs.

A plant cell that does not have a nucleus is the sieve cells which make the sieve tubes. The function of these cells is to transport carbohydrates in different parts of the plant.