At the present time, experiments are being conducted in ______.

A．they provide the means by which people view the size or shape of objects
B．they are the basis for the social feeling of agreement by which society is maintained
C．they encourage people to perform dangerous achievements
D．they generate more love than hate among people

A．they would not be able to tell the texture of objects
B．they would not know what was beneficial and what was harmful to them
C．they would not be happy with a life without love
D．they would do things that hurt each other's feeling