What keeps blood from flowing back into a chamber of the heart

The us council on environmental quality, the world wildlife fund of the united states, the ecological society of america, the smithsonian institution, and the international union for the conservation of nature have proposed four principles of wildlife conservation. which of the following does not apply to wildlife conservation? a) continuous monitoring, analysis, and assessment b) ecosystem maintenance that includes wildlife c) a plan encompassing entire communities of organisms and all renewable resources d) a continued interest in harvesting populations for sport