<prompt> Which of the following is considered as an accurate duplicating material?AgarAlginateImpression compoundNone of the above  <response>: DUPLICATING MATERIALSBoth types of hydrocolloids are used in the dental laboratory to duplicate dental casts or models for the construction of prosthetic appliances and orthodontic models. Agar hydrocolloid is more popular in the lab because it can be used many times. In addition, with intermittent stirring, agar hydrocolloid can be kept in a liquid form for 1 or 2 weeks at a constant pouring temperature. These factors make the cost of reversible impression materials quite reasonable.These property requirements are identified in ANSIADA Specification No. 20 ISO 14356; DentistryDuplicating material.NOTE: Both alginate and agar are considered as accurate impression materials. Owing to the extensive use of agar as a duplicating material, agar can be a better choice.Reference: PHILLIPS SCIENCE OF DENTAL MATERIALS, 12th ed page no 176 