Extensible select and enumeration types

and their elements in schema Observation_arm taking into account BASED_ON types


 activity_item - EXTENSIBLE GENERIC_ENTITY SELECT

 affected_item_select - EXTENSIBLE SELECT

 approval_item - EXTENSIBLE GENERIC_ENTITY SELECT
          Certification
          Contract
          Observation

 certification_item - EXTENSIBLE GENERIC_ENTITY SELECT

 classification_item - EXTENSIBLE GENERIC_ENTITY SELECT
          Observation
          Observation_relationship

 contract_item - EXTENSIBLE SELECT

 date_or_date_time_item - EXTENSIBLE SELECT
          Certification
          Contract
          Observation
          Organization_or_person_in_organization_assignment
          Security_classification_assignment

 event_item - EXTENSIBLE GENERIC_ENTITY SELECT

 identification_item - EXTENSIBLE SELECT
          Approval_status
          Contract
          Organization
          Product_as_individual
          Product_as_individual_version
          Product_as_individual_view
          Security_classification

 measure_value - EXTENSIBLE SELECT
          any_number_value
          any_string_value
          length_measure
          plane_angle_measure

 observation_recorder - EXTENSIBLE SELECT
          Product_as_realized

 observed_context - EXTENSIBLE SELECT

 organization_or_person_in_organization_item - EXTENSIBLE SELECT
          Contract
          Identification_assignment
          Observation
          Security_classification_assignment

 project_item - EXTENSIBLE SELECT

 security_classification_item - EXTENSIBLE SELECT

 string_select - EXTENSIBLE GENERIC_ENTITY SELECT
          Approval
          Approval_relationship
          Approval_status
          Certification
          Contract
          Date_or_date_time_assignment
          Identification_assignment
          Organization_relationship
          Person_in_organization
          Project
          Project_assignment
          Project_relationship