Acid precipitation can harm living organisms in rivers and streams, but some rivers are more vulnerable than others. Streams in the Adirondack Mountains, for example, were quickly acidified by acid precipitation in the 1970s and 80s, killing local trout populations. But rivers that ran through a bed of limestone (calcium carbonate), like the Clark Fork River in Montana, were less affected. What can explain the relative lack of effect of acid precipitation on the Clark Fork River

1. loamy sand is about 80% sand with 10% clay and defined mostly by sand particles with some clay to provide structure and fertility. the sand particles are easily visible and the soil holds structure but breaks apart easily.

2. scott sand can improve his soil quality by incorporating more silt and organic matter into the soil. peat moss and organic matter can also be incorporated.

not sure if this what   you'r looking for would be percent composition

her next move would be to use agarose gel electrophoresis to separate the dna molecules of varying length and create a dna fingerprint.