A．It has always had the same orbit it has now.
B．It used to be much smaller than it is now.
C．It did not always have the same orbit it has now.
D．It is much younger than the rest of the solar system.
A．It is not possible to study their thinking habits.
B．They solve problems in a totally different way.
C．Their muscular movements are not stimulated by ideas.
D．The muscles in their hands move when they solve problems.
A．A study on problem solving took place there.
B．Students' eyes will turn toward it if they think about it.
C．Students should go there to read more about behaviorism.
D．He learned about William James' concept of thinking there.
A．It cannot be completely proved or disproved.
B．It contradicts most of the evidence he has collected.
C．It is the most valid theory of thinking at the present time.
D．It explains adult behavior better than it explains child behavior.