Z: Zooplankton

Zooplankton: A collective term for the nonphotosynthetic organisms present in plankton.

Y: Yeast

Yeast: A unicellular fungus that lives in liquid or moist habitats, primarily reproducing asexually by simple cell division or by budding of a parent cell.

X: Xylem

Xylem: The tube-shaped, nonliving portion of the vascular system in plants that carries water and minerals from the roots to the rest of the plant.

W: Wild Type

Wild Type: An individual with the normal phenotype.

V: Ventricle

Ventricle: A muscular chamber of the heart that receives blood from an atrium and pumps blood out of the heart, either to the lungs or to the body tissues.

U: Urethra

Urethra: A tube that releases urine from the body near the vagina in females or through the penis in males; also serves in males as the exit tube for the reproductive system.

T: T-cell

T cell: A type of lymphocyte responsible for cell-mediated immunity that differentiates under the influence of the thymus.