Here's why:

* Lack of cell wall: Plant cells have a rigid cell wall made of cellulose, which provides structural support. White blood cells, like all animal cells, lack this cell wall.

* Presence of lysosomes: Lysosomes are organelles responsible for breaking down waste products and cellular debris. They are found in animal cells but not in plant cells.

* Centrioles: Animal cells have centrioles, which play a role in cell division. Plant cells do not have centrioles.

White blood cells are a key component of the immune system in animals, and their structure and function are distinctly animal-like.