Here's why:

* Meters (m): This is the unit for distance in the mks system.

* Seconds (s): This is the unit for time in the mks system.

* Acceleration: Acceleration is the rate of change of velocity over time. Since velocity is measured in meters per second (m/s), acceleration is measured in meters per second per second, or meters per second squared (m/s²).

Therefore, the standard unit for acceleration due to gravity (which is a type of acceleration) in the mks system is m/s².