Final answer:
The Fahrenheit scale is least useful for scientific purposes due to its lack of a clear zero point, while the Kelvin scale, starting at absolute zero and using kelvins as units, is the preferred scale for scientific measurements.
Step-by-step explanation:
The Fahrenheit scale is considered to be the least useful temperature scale for scientific purposes primarily because it lacks a clear zero point in temperature. This makes option D the correct choice. Unlike the Kelvin scale, which is an absolute temperature scale starting at absolute zero (0 K), the point at which all molecular motion ceases, the Fahrenheit scale does not have a natural baseline and its unit of temperature, the degree Fahrenheit (°F), does not align with the System International (SI) units used in scientific work.
The Kelvin scale's use of absolute zero and its definition as the temperature scale most often used in scientific contexts make it superior for scientific measurements. This is because it directly relates to physical properties, such as the volume of an ideal gas, and its unit, the kelvin (K), is the SI unit for temperature. The use of kelvins, without a degree sign, acknowledges its status as an absolute scale, reflecting the fundamental physical reality of temperature.