506
Before this date , the drug directly inhibits fetal weight gain , whereas the sensitivity of the placenta is only transient at day 16 resulting in maximum weight decrease of this organ 24 h later .
 None
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: GENE 
Text: {0} 
 Entities:  
Answer:
 None