Cube orange accelerometers

I have the cube orange pixhawk set.
Why there are three accelerometers and three gyros?
How the data is fusioned within those three sensors(accelerometers abd gyros)?
Or there is a priority for one sensor on the others.
Thank you for help!!!

There are three for reundancy.
They work indpendently forming so called EKF cores.
Only one EKF core is active at a time. If one fails another one takes over.