Name one animal cell and one plant cell that has no nucleus when fully developed

In plant cell sieve tubes has no nucleus when fully developed it helps in transportation of minerals and in animal cell the red blood cells has no nucleus when fully developed

igneous rocks which formed by the crystallization of magma at the surface of the earth called extrusive rocks. they are characterized by fine-grained textures because the rapid cooling at or near the surface did not provide enough time for large crystals to grow.