Personality refers to the unique and relatively stable pattern of thoughts, feelings, emotions, behaviours, and psychological characteristics that distinguish one individual from another. It represents the organized and dynamic system within an individual that influences how a person perceives the environment, responds to situations, forms relationships, and adapts to life experiences. According to Gordon Allport, personality is the dynamic organization within the individual of those psychophysical systems that determine unique patterns of behaviour and thought. Thus, personality includes both internal psychological processes and observable behavioural patterns. Personality development is influenced by several factors, including biological, psychological, social, and cultural factors. Biological determinants play a significant role because they provide the basic foundation upon which personality characteristics develop. These biological influences include heredity, genetic factors, brain structure and functioning, nervous system, temperament, and hormonal influences. Heredity is one of the most important biological determinants of personality. Individuals inherit certain characteristics from their parents through genes, which influence physical traits as well as psychological tendencies. Studies of twins and adopted children have shown that genetic factors contribute significantly to personality traits. Identical twins raised separately often show similarities in traits such