Cross-Fostering Experiments Suggest That the Main Reason Primates Do Not

Multiple Choice

Cross-fostering experiments suggest that the main reason primates do not produce human-like variety in their vocalizations is because apes

A) lack the motivation to speak.
B) are not raised in the same language-evoking way human infants are.
C) lack the physical apparatus and control over it to produce human-like speech.
D) cannot breathe and swallow simultaneously.