Suggest a possible hypothesis regarding how the mass of a rock changes when placed in water. identify the independent and dependent variables.
if a rock is placed in water with significant acidic level it will eventually dissolve some of the rock.

what would the independent and dependent variables be?

the nitrogen cycle provides nitrogen to the ecosystem from the atmosphere, ground and oceans. nitrogen is an important component of complex molecules such as amino acids and nucleotides, which lead to the creation of proteins and dna, the building blocks of all life. plants absorb nitrogen in the form of ammonium, nitrate ion and, on rare occasions, as amino acids. animals receive nitrogen necessary for biological processes from feeding on living or dead organic matter.