We know that 'lack of Synthroid' is NOT the cause of any thyroid problem. Exposure to chemicals, e.g. perchlorate, common food intolerances (e.g. wheat/dairy), adrenal fatigue and nutrient deficiencies are the cause of 'hypothyroidism' in the vast majority of cases.
An F3 felony is a shorthand expression for a class or category 3 (or III) felony in jurisdictions that use numbered offense categories. What such an offense is punishable by and whether it is punishable by more or less than an F2 felony depends completely on the laws of the jurisdiction in question.
Nolo lists the following examples: In Missouri, felonies are serious crimes that are punishable by more than one year in prison. Missouri law categorizes felonies into four classes: Class A felonies through Class D felonies. Class A felonies are the most serious felony crimes in Missouri. Class A felonies include murder, first degree kidnapping, forcible rape of a child under twelve years old, first degree robbery, and some drug crimes.