Why sorter transformation is an active transformation?

This is type of active transformation which is responsible for sorting the data either in the ascending order or descending order according to the key specifier. the port on which the sorting takes place is called as sortkeyport. As we have a DISTINCT option to process the distinct records, we can call the Sorter Transformation as an ACTIVE transformation

Properties:

if u select distinct eliminate duplicates 

case sensitive valid for strings to sort the data
null treated low null values are given least priority