What mode of filtration am I?

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Across
  1. 4. the movement of molecules through a semi permeable membrane under the influence of hydrostatic pressure
  2. 5. I am needed before blood goes back to the patient
  3. 6. the flow of molecules across a semi permeable membrane together with a solvent
Down
  1. 1. I am the pump that dilutes the blood
  2. 2. the movement of molecules from an area of high concentration to low concentration
  3. 3. I am the pump that clears away the toxins