Question

What would make a conversion not possible?

Answer 1

if it is already as low as it can go

Answer 2

you generally can't convert between units of mass and volume (e.g., grams to gallons).

Explanation: Examples of Conversion Factors Remember, the two values must represent the same quantity as each other. For example, it's possible to convert between two units of mass (e.g., grams to pounds),