Final answer:
A heritable change in genetic material is called a mutation. This can alter an organism's phenotype, which is different from an allele (a version of a gene), genotype (the genetic makeup), and phenotype (observable traits). Option b is correct answer.
Step-by-step explanation:
A heritable change in the genetic material of an organism is called a mutation. This mutation can lead to a change in the organism's phenotype, which are the observable traits such as height, skin color, or eye color. Mutations occur when there is a change in the DNA sequence, and this change can be passed down through generations. When we consider the possible changes, mutations can be benign, harmful, or even advantageous to the organism, potentially impacting its ability to survive and reproduce.
The term allele refers to one of the different versions of a gene that can exist at a particular gene locus. Alleles can dictate variations in the phenotype of organisms, but an allele itself is not a change in the genetic material; rather, it is a specific version of a gene.
The genotype is the genetic makeup of an individual organism, the combination of alleles for a given gene. The genotype is what carries the potential to produce the phenotype, though not all genotypes are expressed as phenotypical traits.
Phenotype, on the other hand, is the set of observable characteristics of an individual resulting from the interaction of their genotype with the environment.
In summary, a mutation is a change in the DNA sequence that may affect an organism’s phenotype, but it is different from allele, genotype, and phenotype, each of which refers to different aspects of genetic variation and expression.