As a general rule, the greatest vulnerability to _____ occurs during the _____ period of prenatal development.
a. epigenesis; embryonic
b. teratogens; embryonic
c. epigenesis; germinal
d. teratogens; germinal

Respuesta :

Hagrid
The correct answer is letter A, thus the sentence goes: 

As a general rule, the greatest vulnerability to EPIGENESIS occurs during the EMBRYONIC period of prenatal development. 

This is a period in the prenatal development that epigenetic patterns and cell differentiation are intense, hence any factors that are found within the environment can ultimately alter the development of the organism. 
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