If a particle moves at 1 millimeter per microsecond1 \text{ millimeter per microsecond}1 millimeter per microsecond, what is its speed in meters per second?
1 m/s1 \text{ m/s}1 m/s
10 m/s10 \text{ m/s}10 m/s
100 m/s100 \text{ m/s}100 m/s
1000 m/s1000 \text{ m/s}1000 m/s