Final answer:
Neutrophils are the most common type of leukocyte, comprising 50-70 percent of the total leukocyte count. They have distinct lobed nuclei and are called polymorphonuclear neutrophils as they age.
Step-by-step explanation:
The most common type of leukocyte is neutrophils. Neutrophils typically comprise 50-70 percent of the total leukocyte count. They are larger than red blood cells and have distinct lobed nuclei. Younger neutrophils are known as "bands" and as they age, they develop more lobes and are called "polys" or polymorphonuclear neutrophils.