Child Development refers to those physical, intellectual, social, and emotional changes that occur from birth to adolescence. Although people change throughout their lives, developmental changes are especially (31) in childhood. During this period, a dependent, vulnerable newborn grows into a capable young person (32) has mastered language, is self-aware, can think and (33) with sophistication, has a distinctive personality, and socializes (34) with others. Many abilities and characteristics developed (35) childhood last a lifetime. A (36) of factors influence child development. Heredity guides every aspect of physical, (37) , social, emotional, and personality development. Family members, (38) groups, the school environment, and the community influence (39) children think, socialize, and become self-aware. (40) factors such as nutrition, medical care, and (41) hazards in the air and water affect the (42) of the body and mind. Economic and political institutions, the media, and cultural values all (43) how children live their lives. Critical life events, such as a family (44) or a national emergency, can alter the growth of personality and identity. Most important of all, children (45) significantly to their own development. This occurs as they strive to understand their experiences, respond in individual ways (46) the people around them, and choose activities, friends, and interests. Thus, the factors that guide development (47) from both outside and within the person. One reason why the study of child development is important is that it (48) society to support healthy growth. Understanding early brain development, (49) , means that parents can provide better opportunities for intellectual stimulation, and society can reduce or eliminate (50) to healthy brain growth.