If you were asked to convert 25 kg to the unit mg, which of the following would be the first fraction used in the conversion? (2 points)1 kg10 g10 g1kg

The unit mg or milligrams stands for 1 x 10^-6 kg. In the SI system, this is easier to remember since milli prefix stands for 1 x 10^-3 of the base unit. Converting: 25 kg (mg/ 1 x 10^ -6 kg) = 25 x 10^6 mg

It's a

Yes it would be a physical change.