A．They solve a long-standing mystery involving fossil evidence.
B．They contain significant errors that mislead the researchers.
C．They present evidences that conflicts with fossil evidence.
D．Their findings should not have surprised researchers.
A．All modern whales descend from sperm whales.
B．Differences among toothed whales are less significant.
C．Not all toothed whales are closely related.
D．Sperm whales are more closely related to killer whales.
A．They can never be proved or disproved.
B．They were formed without proper evidence.
C．They explain only certain types of the phenomenon.
D．They are contradicted by her research.
A．By recording children's responses to familiar faces.
B．By observing children's reaction to a repeated series of actions.
C．By having children imitate each other's actions.
D．By having children imitate an ordered sequence of actions.