Which explains a difference between prokaryotic and eukaryotic gene regulation?

Which of the following claims does the author support the least

Which type of respiration takes place when there is no oxygen present

Agene pool: a) is the collection of all the alleles found in a single species b) is the collection of all the alleles found in a single population c) is the collection of all the chromosomes found in a single population d) is the collection of genes in a species that allow the individuals to swim