<prompt> In formol ether concentration technique, which layer contain the parasites?EtherFecal debrisFormal waterSediment  <response>: Ans. D. Sediment. Ref. Medical parasitology by Rajesh Karyakarte 1st edpg. 215; Fig. 12-2Concentration techniques include: Sedimentation techniques- Formol ether concentration technique- Formol detergent concentration technique Floatation techniques- Sodium chloride floatation techniques- Zinc sulphate floatation technique- Sugar floatation techniqueFormol ether concentration technique is overall best sedimentation technique. It is rapid and gives good results. The figure shown in reference mentioned clearly shows sediment-containing parasites. 