Question

Why do you think accurate measurements of time became possible much after accurate measurement of length and mass?

Answer 1

The earliest measurements made by us were length and mass. Time was measured in terms of length as distance and time.
Position of sun, moon and stars give idea of days, months and years. Later, mechanical clocks were used to measure time accurately up to minutes. These clocks are based on weights. Today, atomic clocks are used to measure time up to nanoseconds by measuring waves emitted by caesium clock.
Therefore, we think that, over the time, improvements in accuracy in measuring length and mass help in measuring time with more accuracy and precision.