Based on animal experiments, which statement is true regarding genetic effects from radiation exposure?

The correct statement is that all provided options are accurate regarding genetic effects from radiation exposure based on animal experiments.

Genetic mutational damage is indeed more severe with fractionated doses. This means that repeated exposures over time can lead to increased chances of genetic mutations occurring, as the biological systems may have inadequate recovery time between doses. Each fractionated dose can contribute cumulatively to the risk of genetic damage.

Also, the assertion that no threshold dose exists for genetic damage means that there isn't a specific dose below which genetic mutations cannot occur. This concept is significant in radiation protection; even very low levels of radiation may still pose a risk of genetic damage, underscoring the need for caution in radiation exposure.

Additionally, mutational damage being dose-dependent indicates that the severity or likelihood of mutations increases with the amount of radiation received. Larger doses generally lead to a higher probability of damage occurring at the genetic level.

Because all these statements are supported by research and understanding of radiation's impact on genetics, it is accurate to conclude that all of them are true.