what is the primary form of evidence that has led astronomers to conclude that the expansion of the universe is accelerating?

That depends on what kind of environ meant it is in  in space it has the same force that was applied when the velocity was gained

Pe = 1/2k(x)^2  and .05n/m = .05x10^-9m = x 

The answer is water molecules are split.cellular respiration and photosynthesis are complement  reactions to each other. these are reverse reactions. in cellular respiration glucose and oxygen yield water and carbon dioxide. so, when respiration begins,  glucose molecules are split. in the opposite reaction - in photosynthesis, carbon dioxide and water yield glucose and oxygen. thus,  when respiration begins, water molecules are split.

The answer which is not a detail carson used to describe the pool in the cave at low tide is b.  hundreds of periwinkles browse the branches and roots of the trees.