Final answer:
Both of the claims are not entirely supported, as inherited genetic variations arise from a combination of genetic inheritance and environmental influences. Genetics determine the basis for heritable traits, but environment can influence how these genetics are expressed as phenotypes.
Step-by-step explanation:
Neither of the claims—inherited genetic variations are caused by genetics only or that they are caused and influenced by environmental factors only—is fully supported. Inherited genetic variations have a genetic basis; they are passed from parents to offspring according to Mendel's Theory of Inheritance. This genetic transmission influences the genotype of the offspring which in turn can potentially be expressed as phenotypic traits. However, environmental factors—nutrition, climate, experiences—also play a significant role in determining phenotype, which includes physical traits and behaviors.
Therefore, while it is clear that a purely genetic viewpoint does not incorporate the modifying effects of the environment, a purely environmental explanation also fails to acknowledge the necessary genetic basis for heritable traits. For instance, two individuals with the same genotype can express different phenotypes under different environmental conditions, illustrating the concept of genetic environmental correlation. Still, only genetic variations can be inherited and thus subject to natural selection. Genetic drift, gene flow, and mutations further influence allele frequencies in populations, leading to variations in phenotypes. The nature-nurture debate remains complex as both genetics and environment are intricately linked in influencing an individual's traits and behaviors.