Where are most likely to be affected by caner-inducing agents according to the passage（）

A．it is important to build up one’s physical capacity
B．it is no good having much physical training
C．it is more important to know one’s capacity than to win the race
D．it is important to have physical training while one trains his mind

A．The need for agricultural advances to help feed a growing population.
B．The development of safer machines demanded by the labor movement.
C．Machinery that contributed to the agricultural revolution.
D．New Jersey as a leader in the agricultural revolution.