in all organisms, certain genes are expressed at any given time while other genes are not. both prokaryotes and eukaryotes regulate gene expression at the transcription stage. however, the greater complexity of eukaryotic cells makes it possible for gene expression to be regulated at many other stages as well. the diagram below shows different stages at which gene expression may be regulated in eukaryotes.

Ascientist is investigating the effects of salinity on fish development. he places fertilized fish eggs in an aquarium that contains low salinity and observes their development. what factor would improve experimental design the most? place the fish eggs in the open ocean because that is the natural habitat include another aquarium that has normal salinity to compare to the low salinity aquarium include an aquarium that replaces salt with sugar to confirm that the effects are specific to salt grow algae with the fish eggs in order to provide adequate nutrients to the developing embryos