Which statement could be a possible explanation for the drop in mercury concentration in the fish of
onondaga lake between the years 2002 and 2003?
(1) between 2000 and 2005, a large number of fish were sampled.
(2) the dumping of industrial waste was prohibited in 2004.
(3) more young fish were tested in 2003, compared to the other years.
(4) the industrial waste contained more mercury in 2004.