The immune system is designed to protect against microscopic organisms
and foreign substances that enter from outside the body and against some
cancer cells that arise within.
| NSES Content Standard C
Life Science: Structure and function in living systems Grades 5-8, page 156 The human organism has systems for digestion, respiration, reproduction, circulation, excretion, movement, control and coordination, and for protection from disease. These systems interact with one another. |