Final answer:
The statement is true as both allergies and autoimmune diseases are caused by an over-reactive immune system, with allergies being reactions to harmless substances and autoimmune diseases being the result of the immune system attacking the body's own tissues.
Step-by-step explanation:
The statement that allergies and autoimmune diseases both result from an over-reactive immune system is True. Both conditions involve an immune response that is incorrectly targeted or excessively strong. Allergies occur when the immune system reacts to a harmless substance as though it is dangerous, producing an allergic reaction. In contrast, autoimmune diseases involve the immune system mistakenly attacking the body's own tissues, recognizing them as foreign invaders.