How do i tell someone i like him but don't wanna ruin everything?

The outermost layer of your teeth is called the enamel and is made of?

How could you find out if that advice is based in scientific evidence?

The amount of oxygen that is actually used by the body during the rest or a hand workout is determined by the heart rate, the stroke volume, and the amount of a. blood circulating in the vascular system b. oxygen removed from the vascular system c. oxygen provided to the vascular system d. blood that individual has in the body e. hemoglobin in the red blood cells