The biotic values for several different organisms found in a nearby lake are listed below. Organisms with a higher biotic value indicate a healthier body of water If a student sample the
body of water and found 2 Riffle Beetles, 3 Mayfly Nymphs, 6 Clams, 15 Snails and 20 Leeches,
which would be true about the lake ?

try using substitution:

x + y - 6 = x - y. (i'm not giving you the exact answer). since 0 = x - y, then sub 0 in the equation with x - y. combine your like terms, and then use inverse operations, and you'll have your answer.

: -)

frogs. the lower the ph the higher the acid content. frogs have the highest tolerance in this scenario.