Final answer:
Children acquire the ability to understand their world through active engagement with it, developing schemata and adjusting them via assimilation and accommodation. Piaget's theory outlines four stages of cognitive development where children progress from understanding the world through senses to logical abstract thought.
Step-by-step explanation:
Piaget’s theory is based upon the idea that children gradually acquire the ability to understand the world around them through active interaction with it. The correct term to fill in the blank is a) Engagement. According to Jean Piaget, children develop schemata, which are concepts or mental models, to help them categorize and interpret information. As children interact with their environment, they adjust their schemata through two processes: assimilation, where they incorporate new information that is similar to what they know, and accommodation, where they alter their schemata based on new information.
Piaget proposed that cognitive development unfolds in four stages: sensorimotor, preoperational, concrete operational, and formal operational. During these stages, children progress from learning about the world through senses and motor behavior to eventually being able to think logically about abstract concepts and hypothetical situations.