Final answer:
Learning to ride a bicycle from a big wheel or tricycle involves cognitive development processes known as accommodation and assimilation, according to Piaget's theory, with accommodation being the adjustment of existing schemata for new experiences and assimilation being the integration into existing schemata.
Step-by-step explanation:
The question is addressing the concept of learning new skills and how young children make cognitive adjustments when transitioning from one skill to a closely related one. According to Jean Piaget's theory on cognitive development, when children "learn to ride a bicycle" it requires a combination of accommodation and assimilation. When children transition from riding a big wheel to a tricycle, there is less of a cognitive leap because it is 'sort of the same'—this primarily involves assimilation, which is the integration of new experiences into existing schemata (mental models). However, learning to ride a bicycle requires accommodation—adjusting existing schemata to incorporate new experiences. Therefore, the correct answer is B. Accommodation; assimilation.