The process by which leukocytes attack invading microorganisms and clean up cellular debris by consuming the material, or eating cells, is known as .

The leukocytes are capable of attacking and digesting any foreign antigen that enters the body of an organism. The cellular debris is also cleaned by up by these specialized leukocytes known as phagocytes. The digestion of the foreign microorganisms and the cleaning up of the debris is done by phagocytes via the process which is known as phagocytosis. In this process, the phagocyte, engulfs the foreign particle, and the enzymes known as lysosomes digests it.

Hence, the answer is ' phagocytosis'.

a physical change is being made.