Advisory: Completion of CDE-2. Other: Proof of a negative tuberculosis test within the past 12 months may be required for some site visits. Infant and toddler (birth through three years of age) development, as reflected in theory and research findings, including socialization, emotional development and temperament. Appropriate health, safety, and nutritional practices for environments; routines; and culturally sensitive care for infants and toddlers are also covered.