Explanation:

- A parsec is a unit of length.

- It is used in astronomy to measure large distances, equivalent to about 3.26 light-years.

- Acceleration is a change in velocity over time.

- Common units include meters per second squared (m/s²).

- Speed is how fast an object is moving, regardless of direction.

- It is usually measured in meters per second (m/s) or kilometers per hour (km/h).

- Time is the duration in which events occur.

- Common units are seconds, minutes, and hours.