Final answer:
The stage of Erik Erikson's psychosocial development where a child uses imagination to understand complex concepts is Initiative vs. Guilt, occurring from ages 3 to 6.
Step-by-step explanation:
According to Erik Erikson's theory of psychosocial development, the scenario described where a child uses their imagination to understand concepts like reproduction, growth, future, and death is part of the stage of Initiative vs. Guilt. This stage typically occurs in the preschool years, between the ages of 3 to 6. Within this stage, children begin to assert control and power over their environment through initiating activities and play. Successful navigation of this stage leads to a sense of purpose and self-confidence, whereas failure to resolve the conflicts can result in feelings of guilt.