In general, an employer must pay you for every hour that you work. This even includes time that the employer feels you did not do a good job. The employer can write you up or discipline you in other ways, but he or she cannot withhold pay for hours worked.
If you are not being paid for all the hours that you worked, you should contact the U.S. Wage and Hour Division, or your state Department of Labor.
strike ... or resignation.
Yes, the employer can ask. But you can always refuse and take the consequences.
If your employer does not provide you with an appropriate MSDS you may refuse to work with the product after one working day.
Yes
Strike or Boycott
Not positive, but No, you must be paid for any work for/from your employer or you can refuse to do it. However whatever you broke or anything they can deduct from your check.
if another employee made a mistake can my employee make me fix it for free and if i refuse can he fire me
Breaks are a matter of state law or employer policy.
Yes, if the employee is no longer capable of performing one or more essentila work functions, or poses a danger to self or others.
Yes, unless the company can effectively prove that it would be "Undue Hardship" for them, if they did accommodate.
Sure he can refuse to pay you. You can also sue him in small claims court to try and recover lost wages. That may very well be you last resort if he refuses to pay you.
If your question is "When I miss hours of work, can the employer refuse to call them paid vacation as I requested", the answer is "Goodness yes, the employer alone determines the vacation usage policy.