4569
In the results , the effective activity of Cu , { Cu ( 2 + ) } , resulting in a 50 % reduction of root elongation ( EA ( 50 ) ) , linearly increased with increments of Mg activity , { Mg ( 2 + ) } .
 Chemical: Cu; Chemical: Cu ( 2 + ); Chemical: Mg; Chemical: Mg ( 2 + )
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: Cu; Chemical: Cu ( 2 + ); Chemical: Mg; Chemical: Mg ( 2 + )