there are specific critical periods during fetal development in which any damage caused to the fetus from malnutrition or exposure to toxins is irreversible. when do these periods occur?

The scales shown in the introduction measure mass, or the amount of matter in a particular object. the scientific law of conservation of mass states that matter cannot be created or destroyed during a chemical reaction, but it can change from one form to another. did the simulation support this scientific law? explain why or why not.