What aré the internal biological functions control by?

Internal biological functions are primarily controlled by the endocrine and nervous systems. The endocrine system uses hormones to regulate processes such as metabolism, growth, and reproduction, while the nervous system coordinates rapid responses to stimuli through electrical signals. Together, these systems maintain homeostasis, ensuring that the body's internal environment remains stable despite external changes. Additionally, cellular signaling pathways play a crucial role in regulating various physiological processes.