Final answer:
Phagocytosis is the process that animals use to engulf, digest, and destroy invading bacteria by enclosing the pathogen within a phagosome and digesting it in a phagolysosome using digestive enzymes and acids.
Step-by-step explanation:
Phagocytosis is the process that animals use to engulf, digest, and destroy invading bacteria. When a pathogen such as a bacterium is encountered by a phagocyte, the phagocyte extends a portion of its plasma membrane, wrapping the membrane around the pathogen until it is enveloped.
Once inside the phagocyte, the pathogen becomes enclosed within an intracellular vesicle called a phagosome. The phagosome then fuses with another vesicle called a lysosome, forming a phagolysosome.
Digestive enzymes and acids from the lysosome kill and digest the pathogen in the phagolysosome. The final step of phagocytosis is the excretion of soluble debris from the destroyed pathogen through exocytosis.