Indicate the metric unit for: mass, length, and volume

1.  Indicate the metric unit for:  a)  mass,  b)  length, and  c)  volume

2.  The time is recorded from three different clocks as indicated below.  The “true” time is exactly 8:30 A.M.

  a)  Which of the three clocks is the most precise?  b)  Which clock is the most accurate?

  c)  Which clock(s) show a systematic error?