The ideal title for this passage is （）

A．the working system of the electric plates in the eel is the most effective
B．the working system of the electric plates in the eel is far inferior to those in the torpedo
C．compared with those in the torpedo, the working system of electric plates in the eel is more direct and efficient
D．compared with other electric fish, the eel possesses much more electric plates

A．a basic human desire to understand and control the world
B．the satisfaction of certain physiological needs
C．their strong desire to solve complex problems
D．a fundamental human urge to display their learned skills

A．would make learned responses when it saw the milk
B．would carry out learned movements when it had enough to drink
C．would continue the simple movements without being given milk
D．would turn its head to right or left when it had enough to drink