How to check process and session in Oracle?

--- For sessions
SQL> select RESOURCE_NAME,CURRENT_UTILIZATION,MAX_UTILIZATION,LIMIT_VALUE from v$resource_limit where resource_name = 'sessions';
 RESOURCE_NAME                  CURRENT_UTILIZATION MAX_UTILIZATION LIMIT_VALU
------------------------------ ------------------- --------------- ----------
sessions                                       121             506       6032
  ---- For processes
SQL> select RESOURCE_NAME,CURRENT_UTILIZATION,MAX_UTILIZATION,LIMIT_VALUE from v$resource_limit where resource_name = 'processes';
 RESOURCE_NAME                  CURRENT_UTILIZATION MAX_UTILIZATION LIMIT_VALU
------------------------------ ------------------- --------------- ----------
processes                                      173             527       4000
 SQL>

select * from DBA_HIST_RESOURCE_LIMIT where resource_name in ('sessions','processes');

select s.SNAP_ID,TO_CHAR(s.END_INTERVAL_TIME, 'DD-MON HH24:MI:SS') Snapshottime,resource_name,current_utilization,max_utilization,limit_value from DBA_HIST_SNAPSHOT s, DBA_HIST_RESOURCE_LIMIT b
where s.snap_id = b.snap_id and resource_name in ('sessions') order by 2;