What is defined as the complete set of genetic instructions inherited by an organism?

The term that defines the complete set of genetic instructions inherited by an organism is "genome." A genome encompasses all of the genetic material in an organism, including both the genes that are expressed and the non-coding sequences of DNA. It represents the entire hereditary information passed down from one generation to the next.

In contrast, a chromosome is a structure within the cell that contains tightly coiled DNA and proteins, serving as a packaging unit for genetic material. While chromosomes are important for organizing the genome, they do not represent the complete set of genetic instructions by themselves.

Phenotype refers to the observable characteristics or traits of an organism, which result from the interaction between its genotype (the genetic makeup) and the environment. Thus, phenotype is an expression of the genome, not the genome itself.

Genotype refers specifically to the genetic makeup of an individual, often concerning specific genes or alleles, whereas the genome includes all of the individual's DNA, encompassing every gene and sequence present in the organism. Therefore, "genome" is the most accurate choice for the complete set of genetic instructions inherited by an organism.