What is the biological pump?

What is the biological pump?
 
  a) Osmosis pushes nutrients across cell membranes, allowing the nutrients to get from the bloodstream to where they are needed by the cells.
  b) Photosynthetic organisms take in carbon dioxide and give off oxygen.
  c) Photosynthetic organisms use sunlight, carbon dioxide, and water to create energy.
  d) The removal of nitrogen from the water by biologic productivity
  e) The removal of organic matter and nutrients from surface water to deep water through the sinking of dead surface-dwelling organisms