which includes the physical characteristics of an organism?\no gene\no allele\no genotype\no phenotype

Brief Explanations:

A phenotype encompasses the observable physical and physiological traits of an organism, which are the result of the interaction between its genetic makeup (genotype) and the environment. A gene is a unit of heredity, an allele is an alternative form of a gene, and genotype refers to the genetic constitution of an organism.

Answer:

D. phenotype