Here's why:
* Function: Red blood cells are responsible for transporting oxygen throughout the body. To maximize their efficiency, they need to be small and flexible to squeeze through tiny capillaries.
* Nucleus Removal: During their development, red blood cells eject their nucleus and other organelles to make room for more hemoglobin, the protein that binds to oxygen. This process is called enucleation.
* Lifespan: Without a nucleus, red blood cells cannot replicate or repair themselves. They have a lifespan of about 120 days.
While red blood cells are the only human cells without a nucleus, it's important to remember that all cells need a nucleus at some point in their development.
