From which two parts of an outside micrometer do you obtain readings?

The correct answer is based on how an outside micrometer is designed to take precise measurements. The sleeve and thimble are the two main components involved in obtaining readings.

The sleeve is usually marked with a scale that provides a complete measurement scale. As the thimble is rotated, it moves the measuring spindle closer to or further from the anvil, allowing for minute adjustments in measurement. The thimble also has graduations that, when combined with the sleeve's scale, provide a precise reading of the measurement being taken.

The other components mentioned in the other options do not serve the purpose of reading measurements. For instance, while the anvil and base provide the surfaces for measurement, they do not display the measurement itself. The barrel and spindle functions are related to the mechanics of how measurements are taken, but they do not include the crucial graduated parts for reading. The frame and disk are structural components and do not aid in the measurement reading process.