4658
The ability of Nitzschia palea to increase the production of frustulins due to the presence of Cd , the extracellular location of this frustulin coating and the ability of these proteins to bind Cd , suggests a new cellular defense mechanism to metals unknown until now .
 Chemical: Cd; Chemical: Cd
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: Cd, Cd 
Answer:
 Chemical: Cd; Chemical: Cd