20093
The objective of the present study was to compare and characterize the symbiotic efficiency of N2 fixation of M . truncatula and M . sativa grown in sand under P - limitation .
 Chemical: N2; Chemical: P
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: N2, P 
Answer:
 Chemical: N2; Chemical: P