Final answer:
The question highlights the critical nature of using correct units in measurements, notably in chemistry and medicine, to ensure safety and precision. It exemplifies the necessity for standards such as liters, pounds, and centimeters, and the importance of manageable unit expressions like milligrams and kilograms.
Step-by-step explanation:
The question is about the importance of specifying units when dealing with measurements, which is especially crucial in fields like chemistry and medicine, where the outcome can be life-threatening if units are not used correctly. For example, without specifying units, a prescribed dosage of "100" for phenobarbital could lead to confusion and potentially fatal consequences. The correct dosage of 100 mg could be effective, but 100 g could be lethal. This illustrates why units such as liters, pounds, and centimeters are necessary standards of comparison for measurements.
Meanwhile, expressing units in a manageable number makes practical sense. For instance, converting the mass of a 5.00-grain aspirin tablet to milligrams involves understanding that 1 grain is equal to 0.00229 oz, showing how units enable precise and safe medication dosages. In a chemistry context, a ratio such as 1 mg being equivalent to 1 × 10⁻³ g highlights the process of unit conversion that is fundamental for chemists. Knowing how to convert units accurately is imperative for professionals in this field.