Genetic constitution of an organism is known as

Explaination:-

A: The genetic constituent of an organism is known as Genotype,which is a genetic form of an organism.

B: Morphological or an external appearance of an organism is known as phenotype.

C: Trait is a genetically determined character.

D: An allele is a variant versions/form of gene.

Final Answer:-

Hence the correct option is A i.e Genotype