Question

why is it necessary to include units when reporting scientific measurements?
units must be included with the number to compare results of various measurements.
units indicate the number of significant figures in the value.
units must be included with the number to make measurements more complicated. it is very simple to report them without units.
none of the above

Explanation:

Units are crucial in scientific measurements. They provide context to the numerical value. Without units, a number like 5 could mean 5 meters, 5 seconds, 5 grams etc. When comparing different measurements (e.g., length of two objects), if one is measured in meters and another in centimeters (without units mentioned), comparison is impossible. Significant figures are determined by the digits in the number, not the unit. Also, units do not complicate measurements - they clarify them.

Answer:

Units must be included with the number to compare results of various measurements.