Every conversion ratio is a factor of one, must have equal numbers in both numerator and denominator, and must give the square of a power when used for changing units. Which of the following statements is true about conversion ratios?
1) Conversion ratios are not related to units
2) Conversion ratios can have different numbers in the numerator and denominator
3) Conversion ratios are always equal to one
4) Conversion ratios can be used to change units without squaring the power
