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        <ExplanationTxt>THE FORM 990 OF THE REPORTING ORGANIZATION, THE NATIONAL ACADEMY OF SCIENCES RETIREE WELFARE BENEFIT PLAN TRUST, IS REVIEWED BY A REPRESENTATIVE OF THE TRUSTEE PRIOR TO FILING.</ExplanationTxt>
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        <FormAndLineReferenceDesc>FORM 990, PART VI, LINES 1A, 12, 13, 14 &amp; 15:</FormAndLineReferenceDesc>
        <ExplanationTxt>THE REPORTING ORGANIZATION IS A TRUST WITH A GOVERNING BODY COMPRISING A SINGLE INSTITUTIONAL TRUSTEE, EXETER TRUST COMPANY. THE TRUST IS SUBJECT TO A WRITTEN TRUST AGREEMENT THAT REQUIRES THE TRUSTEE TO DISCHARGE ITS DUTIES CONSISTENT WITH ITS ROLE AS A FIDUCIARY UNDER ERISA. THERE IS NO SEPARATE CONFLICT OF INTEREST POLICY, RECORD RETENTION, OR WHISTLEBLOWER POLICY APPLICABLE TO THE TRUSTEE. THE REPORTING ORGANIZATION REQUIRES THE TRUSTEE TO COMPLY WITH THE TRUST AGREEMENT AND ITS FIDUCIARY OBLIGATIONS UNDER ERISA. THE TRUST HAS NO EMPLOYEES OR KEY PERSONNEL AND DOES NOT PAY COMPENSATION TO ANY PERSON LISTED ON PART VI, LINE 15.</ExplanationTxt>
      </SupplementalInformationDetail>
    </IRS990ScheduleO>
    <IRS990ScheduleR documentId="RetDoc1043400001">
      <IdRelatedTaxExemptOrgGrp>
        <DisregardedEntityName>
          <BusinessNameLine1Txt>NATIONAL ACADEMY OF SCIENCES</BusinessNameLine1Txt>
        </DisregardedEntityName>
        <USAddress>
          <AddressLine1Txt>2101 CONSTITUTION AVE NW</AddressLine1Txt>
          <CityNm>WASHINGTON</CityNm>
          <StateAbbreviationCd>DC</StateAbbreviationCd>
          <ZIPCd>20418</ZIPCd>
        </USAddress>
        <EIN>530196932</EIN>
        <PrimaryActivitiesTxt>SCI. RESEARCH</PrimaryActivitiesTxt>
        <LegalDomicileStateCd>DC</LegalDomicileStateCd>
        <ExemptCodeSectionTxt>501(C)(3)</ExemptCodeSectionTxt>
        <PublicCharityStatusTxt>LINE 7</PublicCharityStatusTxt>
        <DirectControllingNACd>N/A</DirectControllingNACd>
        <ControlledOrganizationInd>0</ControlledOrganizationInd>
      </IdRelatedTaxExemptOrgGrp>
      <ReceiptOfIntAnntsRntsRyltsInd>0</ReceiptOfIntAnntsRntsRyltsInd>
      <GiftGrntOrCapContriToOthOrgInd>0</GiftGrntOrCapContriToOthOrgInd>
      <GiftGrntCapContriFromOthOrgInd>0</GiftGrntCapContriFromOthOrgInd>
      <LoansOrGuaranteesToOtherOrgInd>0</LoansOrGuaranteesToOtherOrgInd>
      <LoansOrGuaranteesFromOthOrgInd>0</LoansOrGuaranteesFromOthOrgInd>
      <DivRelatedOrganizationInd>0</DivRelatedOrganizationInd>
      <AssetSaleToOtherOrgInd>0</AssetSaleToOtherOrgInd>
      <AssetPurchaseFromOtherOrgInd>0</AssetPurchaseFromOtherOrgInd>
      <AssetExchangeInd>0</AssetExchangeInd>
      <RentalOfFacilitiesToOthOrgInd>0</RentalOfFacilitiesToOthOrgInd>
      <RentalOfFcltsFromOthOrgInd>0</RentalOfFcltsFromOthOrgInd>
      <PerformOfServicesForOthOrgInd>0</PerformOfServicesForOthOrgInd>
      <PerformOfServicesByOtherOrgInd>0</PerformOfServicesByOtherOrgInd>
      <SharingOfFacilitiesInd>0</SharingOfFacilitiesInd>
      <PaidEmployeesSharingInd>0</PaidEmployeesSharingInd>
      <ReimbursementPaidToOtherOrgInd>1</ReimbursementPaidToOtherOrgInd>
      <ReimbursementPaidByOtherOrgInd>0</ReimbursementPaidByOtherOrgInd>
      <TransferToOtherOrgInd>0</TransferToOtherOrgInd>
      <TransferFromOtherOrgInd>0</TransferFromOtherOrgInd>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>SCHEDULE R, PART II:</FormAndLineReferenceDesc>
        <ExplanationTxt>THE NATIONAL ACADEMY OF SCIENCES IS A FEDERALLY CHARTERED TAX-EXEMPT CORPORATION CHARTERED BY AN ACT OF CONGRESS IN 1863 AND IS NOT A DISTRICT OF COLUMBIA CORPORATION.</ExplanationTxt>
      </SupplementalInformationDetail>
    </IRS990ScheduleR>
  </ReturnData>
</Return>