Biological influences refer to the ways in which genetics and physiological processes affect behavior, development, and health. These influences can include inherited traits from parents, such as genetic disorders or physical characteristics, as well as the impact of hormones and neurotransmitters on mood and behavior. Additionally, environmental factors, like nutrition and exposure to toxins, can interact with biological systems, shaping an individual's overall well-being. Understanding these influences is crucial in fields like psychology and medicine, as they help explain variations in behavior and health outcomes among different individuals and populations.