Why do scientists apply the concept of maximum parsimony?
to decipher accurate phylogenies
to eliminate analogous traits
to identify mutations in dna codes
to locate homoplasies

to decipher accurate phylogenies

Explanation:

The principle or criteria of using maximum parsimony in evolution genetics is use because of the next premise:

"the most possible evolutionary history is the one with the easiest one".  

In other words, the more complicated a predicted phylogenetic tree is, the fewer the possibility that it describes an evolution process correctly, statistially speaking.

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.

: -)

when atoms of different types of elements join together, they make molecules called compounds. water consists of compound molecules made up of 2 hydrogen atoms and 1 oxygen atom. this is why it's called h2o. water will always have 2 times the number of hydrogen atoms as oxygen atoms.