This Graph Illustrates Embryonic/fetal Development Throughout Pregnancy, Including Organ System

This graph illustrates embryonic/fetal development throughout pregnancy, including organ system development. Review the information provided in this graph, then respond to the following: Define the term teratogen, Why are there certain periods when damage from teratogens is likely to be greatest and other times when the damage may be less severe for a given organ system? Why do these time periods differ for different organ systems?