Photosynthesis and cellular respiration are both complementary and relatively balanced, but early history of life on Earth showed increasing oxygen concentrations. This indicates that Group of answer choices both photosynthesis and respiration were occurring at approximately the same levels. neither photosynthesis nor respiration were occurring. the amount of cellular respiration occurring exceeded the amount of photosynthesis. the amount of photosynthesis occurring exceeded the amount of cellular respiration.

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