पियाजे के सिद्धांत के अनुसार पूर्व-संक्रियात्मक अवस्था (2-7 वर्ष) के दौरान आमतौर पर कौन सी संज्ञानात्मक विशेषता प्रकट होती है?

According to Jean Piaget, mathematical knowledge is primarily acquired through:

How does Piaget's theory explain children's process of learning mathematical concepts?

A Class 2 teacher notices that when she pours water from a short, wide glass into a tall, thin one, her students insist that the taller glass holds more water. Based on Piaget's theory, which stage of cognitive development are these students most likely in, and what concept are they struggling with?