Answer: conservation

AnswerCrossword Clue
CONSERVATIONSierra Club concern
CONSERVATIONSubject of J. F. K. message.
conservationPrevention of excessive or wasteful use of a resource
conservationThe principle by which the total value of a physical quantity (such as energy, mass, or linear or angular momentum) remains constant in a system
conservationPreservation, protection, or restoration of the natural environment, natural ecosystems, vegetation, and wildlife
conservationThe action of conserving something, in particular
conservationa careful preservation and protection of something