Directions: Select the correct diagram. The diagrams below represent the fossils of shellfish in four hypothetical cross sections of a canyon. The top layers are the
youngest layers, and the bottom layers are the oldest
Which cross section could be used as evidence that, over time, a circular shellfish descended from a hexagonal shellfish?
1
2
3

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