In classical genetics and evolutionary biology, which statement best describes the nature of genetic variations in a population? Choose the option that reflects their persistence and heritability rather than short lived environmental effects.

Introduction / Context:
Genetic variation refers to differences in DNA sequences among individuals of a species. These differences arise through mutation, recombination, and other genomic processes and provide the raw material for evolution by natural selection. The key attribute of genetic variation is that it resides in the genotype and is transmissible across generations, making it relatively stable compared with purely environmental or physiological changes.

Given Data / Assumptions:

• The term variation is being used in a genetic sense, not short term physiological acclimation.
• Heritability implies that the underlying DNA change can pass from parents to offspring.
• Environmental influences can alter phenotype without altering DNA sequence.

Concept / Approach:
Mutations that change nucleotide sequences create genetic variants. Once incorporated into germline DNA (or the entire genome in single celled microbes), these variants persist unless removed by counter mutation or selection. Phenotypic traits can be influenced by environment, but unless the DNA itself changes, those effects are not genetic. Therefore, genetic variations are characterized by stability and heritability.

Step-by-Step Solution:
Identify that genetic variation refers to DNA sequence differences. Connect DNA based differences to inheritance across generations. Contrast with environmental effects that do not alter DNA. Select the option that captures persistence and heritability: stable.

Verification / Alternative check:
Population genetic models treat allele frequencies as stable quantities that change only via mutation, migration, selection, and drift, underscoring that genetic differences are not merely transient environmental responses.

Why Other Options Are Wrong:

• Temporary: suggests short lived, which contradicts heritable DNA level changes.
• Influenced by the environment: environment can affect phenotype, but that does not define genetic variation.
• Not heritable: contradicts the core definition of genetic variation.

Common Pitfalls:
Confusing epigenetic or physiological acclimation with true genetic change; only sequence level alterations constitute genetic variation in the strict sense.

Final Answer:
stable