Direction: Choose the appropriate answer from the options given below :

Nucleus is present in all the eukaryotic cells, except the ______ of the man.

Mature red blood cells (erythrocytes) in mammals lose their nucleus during development to make more space for hemoglobin, which carries oxygen. This adaptation allows RBCs to be flexible enough to squeeze through tiny capillaries. Liver cells, stomach cells, and karyotype (which is a chromosome arrangement, not a cell type) all contain nuclei.