Final answer:
The gland that stimulates the immune system is the thymus.
Step-by-step explanation:
The gland that stimulates the immune system is the thymus. The thymus is a small organ located in the chest, behind the breastbone. It plays a crucial role in the development and maturation of T-lymphocytes, which are white blood cells that are a key part of the immune system.
Learn more about immune system stimulation