Need to unset pga_aggregate_limit

In my Environment  we have to unset pga_aggregate_limit ,As far i understand  pga_aggregate_limit  is hard limit , if pga_aggregate_limit is more than PGA_AGGREGATE_TARGET

Oracle sets the default by picking the biggest value from:

• 2 GB or
• 200% of the PGA_AGGREGATE_TARGET value or
• 3 MB times the value of the PROCESSES parameter

In my environment ,pga_aggregate_limit  is less then pga_aggregate_target,

Question 1) IS it possible pga_aggregate_limit less then pga_aggregate_target

Question 2) if i unset what will be impact of that

SQL> show parameter PGA

NAME                                 TYPE        VALUE

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