In recent scientific history, the classification of the protist kingdom has changed several times. They are now grouped to consider their development over time instead of simply by what they look like or how they move. Which statement best describes the reason for these classification changes?

A. Traditional scientists did not have enough information about protists to attempt to clasify them.
B. Originally, scientists drew inaccurate conclusions about the classification of protists based on flawed data.
C. Changes in classification of this kingdom are made each time modern scientists discover a new species of protists.
D. The classification of protists changes as scientists learn more about how these organisms are related to each other and to members of other kingdoms.