5182
Mn ( 2 + ) is transported into cells via a number of mechanisms , while Mn ( 3 + ) is believed to be transported similarly to iron ( Fe ) via the transferrin ( Tf ) mechanism .
 Mn ( 2 + ), Mn ( 3 + ), iron, Fe
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 Mn ( 2 + ), Mn ( 3 + ), iron, Fe