Blood consists of different types of cells — red blood cells, platelets, and white blood cells. Red blood cells transport oxygen throughout the body, platelets aid in blood clotting, and white blood cells help destroy and remove old cells and foreign substances. This is an example of how
A. different cells are unable to be grouped together within the same organ or organ system.
B. only similar cells are grouped together so they can perform a singular function.
C. every part of the body contains different cells with unique and unrelated functions.
D. the cells of the body are of different kinds and are grouped in ways that enhance how they function together.