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        <ExplanationTxt>DESCRIPTION OF ORGANIZATION MISSION: THE REPORTING ORGANIZATION, NATIONAL ACADEMY OF SCIENCES RETIREE WELFARE BENEFIT PLAN TRUST (THE TRUST) WAS ORGANIZED AND WILL OPERATE FOR THE BENEFIT OF THE NATIONAL ACADEMY OF SCIENCES (NAS) FOR THE PRIMARY PURPOSE OF HOLDING, MANAGING AND INVESTING CERTAIN ASSETS OF THE NATIONAL ACADEMY OF SCIENCES RETIREE WELFARE BENEFIT PLAN (PLAN) SAID ASSETS TO BE HELD IN TRUST FOR THE PURPOSE OF PAYING INSURANCE</ExplanationTxt>
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        <FormAndLineReferenceDesc>PARTVI SECT A LINE 8A</FormAndLineReferenceDesc>
        <ExplanationTxt>MANAGEMENT OF THE TRUST DOES NOT INVOLVE MEETINGS THAT REQUIRE CONTEMPORANEOUS RECORDKEEPING. UNDER THE TRUST, THE TRUSTEE IS REQUIRED TO KEEP AND MAINTAIN COMPLETE AND ACCURATE RECORDS OF ALL ASSETS AND TRANSACTIONS OF THE TRUST FUND.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>PART VI SEC A LINE 8B</FormAndLineReferenceDesc>
        <ExplanationTxt>SEE EXPLANATION FOR FORM 990, PART VI, SECTION A, LINE 8A.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>PART VI SEC B LINE 11B</FormAndLineReferenceDesc>
        <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>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>PART VI SEC C LINE 19</FormAndLineReferenceDesc>
        <ExplanationTxt>DOCUMENTS CAN BE REVIEWED BY WRITTEN REQUEST IN THE OFFICES OF THE TRUSTEE.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>PART IV LINE 12</FormAndLineReferenceDesc>
        <ExplanationTxt>AUDITED FINANCIAL STATEMENTS ARE PREPARED FOR THE PLAN (WHICH INCLUDES CERTAIN TRANSACTIONS SUCH AS THE PAYMENT OF ANNUAL INSURANCE PREMIUMS THAT ARE PAID DIRECTLY BY THE PLAN SPONSOR OR INDIVIDUAL PARTICIPANTS IN THE PLAN). NOTE THAT ANNUAL PREMIUMS PAYABLE UNDER THE PLAN BY THE PLAN SPONSOR (NATIONAL ACADEMY OF SCIENCES) MAY BE PAID EITHER DIRECTLY BY THE PLAN SPONSOR OR MAY BE PAID THROUGH THE TRUST.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>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</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>PART III LINE 4D</FormAndLineReferenceDesc>
        <ExplanationTxt>AUDIT AND ACTUARIAL FEES</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>PART XI lINE 9</FormAndLineReferenceDesc>
        <ExplanationTxt>N/A</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>EXPLANATION FOR FORM 990, PAGE 2, PART III, LINE 4d</FormAndLineReferenceDesc>
        <ExplanationTxt>AUDIT AND ACTUARIAL FEES</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>EXPLANATION FOR FORM 990, PAGE 6, PART VI, LINE 8a</FormAndLineReferenceDesc>
        <ExplanationTxt>MANAGEMENT OF THE TRUST DOES NOT INVOLVE MEETINGS THAT REQUIRE CONTEMPORANEOUS RECORDKEEPING AND ACCURATE RECORDS OF ALL ASSETS AND TRANSACTIONS OF THE TRUST FUND</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>EXPLANATION FOR FORM 990, PAGE 6, PART VI, LINE 8b</FormAndLineReferenceDesc>
        <ExplanationTxt>SEE EXPLANATION FOR FORM 990, PART VI, SECTION A, LINE 8A</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PAGE 6, PART VI, LINE 11-DESCRIPTION OF PROCESS FOR REVIEW</FormAndLineReferenceDesc>
        <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>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PAGE 6, PART VI, LINE 18</FormAndLineReferenceDesc>
        <ExplanationTxt>SEE SCHEDULE O</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PAGE 6, PART VI, LINE 19</FormAndLineReferenceDesc>
        <ExplanationTxt>EXETER TRUST COMPANY 290 WOODCLIFF DRIVE FAIRPORT NY 11450 585-325-1129</ExplanationTxt>
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      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>EXPLANATION FOR FORM 990, PART XI, LINE 9</FormAndLineReferenceDesc>
        <ExplanationTxt>N/A</ExplanationTxt>
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          <CityNm>WASHINGTON</CityNm>
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        <PrimaryActivitiesTxt>SCI. RESEARCH</PrimaryActivitiesTxt>
        <LegalDomicileStateCd>DC</LegalDomicileStateCd>
        <ExemptCodeSectionTxt>501(c)(3)</ExemptCodeSectionTxt>
        <PublicCharityStatusTxt>THE NATIONAL ACADEMY</PublicCharityStatusTxt>
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      <LoansOrGuaranteesToOtherOrgInd>false</LoansOrGuaranteesToOtherOrgInd>
      <LoansOrGuaranteesFromOthOrgInd>false</LoansOrGuaranteesFromOthOrgInd>
      <DivRelatedOrganizationInd>false</DivRelatedOrganizationInd>
      <AssetSaleToOtherOrgInd>false</AssetSaleToOtherOrgInd>
      <AssetPurchaseFromOtherOrgInd>false</AssetPurchaseFromOtherOrgInd>
      <AssetExchangeInd>false</AssetExchangeInd>
      <RentalOfFacilitiesToOthOrgInd>false</RentalOfFacilitiesToOthOrgInd>
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      <PerformOfServicesByOtherOrgInd>false</PerformOfServicesByOtherOrgInd>
      <SharingOfFacilitiesInd>false</SharingOfFacilitiesInd>
      <PaidEmployeesSharingInd>false</PaidEmployeesSharingInd>
      <ReimbursementPaidToOtherOrgInd>true</ReimbursementPaidToOtherOrgInd>
      <ReimbursementPaidByOtherOrgInd>false</ReimbursementPaidByOtherOrgInd>
      <TransferToOtherOrgInd>false</TransferToOtherOrgInd>
      <TransferFromOtherOrgInd>false</TransferFromOtherOrgInd>
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        <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>
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