The Process of Song Learning by White-Crowned Sparrows Is Similar

The process of song learning by white-crowned sparrows is similar to the process of territory-holding by African cichlid fishes because brain cells in both animals can change ____ in response to well-defined social stimuli.

A) only their biochemistry
B) only their structure
C) only their function
D) only their structure and function
E) their biochemistry, structure, and function