Concept:Learning curve is a graphical representation of the relationship between practice or trials and the level of learning achieved.
Explanation:It shows how learning changes over time, usually gradually, as a person practices.
Different types exist: increasing returns, decreasing returns, and S-shaped curves.
But in all cases, the curve reflects a continuous, gradual changing process of learning.
It does not show only decline or a fixed ratio.
Answer:A. gradual changing process of learning
