Explanation:

Fischer projections were originally proposed for the depiction of carbohydrates and used by chemists, particularly in organic chemistry and biochemistry. A Fischer projection always uses an eclipsed conformation. A Newman diagram can represent either an eclipsed conformation or a staggered conformation or a skew conformation. Just as with Newman projections, you can draw sawhorse projections in eclipsed and staggered conformations. Since staggered conformation is more stable than eclipsed one, Fischer projection being in eclipsed projection represents least stable conformation.