Tar, carbon monoxide, arsenic, vinyl chloride, and/or formaldehyde
Answer: All of the above.
The ability to lift a weight 12 times or more is not optimal for growing muscle mass. If you can't lift a weight eight or more times you are also not optimally building muscle mass. Generally speaking, the target goal for lifting weights to build muscle is anywhere between eight and 12 reps.
Formulary would be a correct answer
