The length of a rod can be used as the standard measurement for a metre
Which of the following are reasons why a rod cannot be used as a standard for measuring length?
A cloth merchant uses a metre rod for measuring the length of the cloth piece, while a tailor uses a tape for measurement.
Statement 1: A rod can be used as a standard unit.
Statement 2: Length of the rod is not constant at all temperatures.
Why can we not use the length of a rod as a standard unit?