Question

describe the fischer's structure of D-glyceraldehyde molecule ​

Answer 1

Below are two different representations of (R)-glyceraldehyde, the smallest sugar molecule (also called D-glyceraldehyde in the stereochemical nomenclature used for sugars): ... While Fischer projections are used for sugars in their open-chain form, Haworth projections are often used to depict sugars in their cyclic forms.