If you are like most people,your intelligence changes from season to s

If you are like most people,your intelligence changes from season to s
.You are probably a lot sharper in the spring than you are at any other time of year.A famous scientist,Ellsworth Huntington (1876-1974),concluded (得出结论) from other men’s work and his own among people in different climates that climate and temperature have a certain effect on most people’s mental abilities.
He found that cool weather is much more favorable (有利的,起促进作用的) for creative thinking than summer heat.This does not mean that all people are less intelligent in the summer than they are during the rest of the year.It does mean,however,that the mental abilities of large numbers of people tend to be the lowest in the summer.
Spring appears to be the best period of the year for thinking.One reason may be that in the spring man’s mental abilities are affected by the same factors（因素） that bring about great changes in all nature.
Fall is the next-best season,then winter.As for summer,it seems to be good time to take a long vacation from thinking!
1、The word “sharper” in the first paragraph probably means_______________.
A.slower B.stronger C.taller D.smarter
2、Huntingtonbased his conclusions on ___________________.
A.records of his own research work
B.records given by other people
C.records of temperature changes
D.both A and B