PLEASE HELP! before paine recalled that a year after the starfish had been removed the number of species that decreased from 15 to 8 after three years the number went down to 7 and after another seven years it was almost all only mussels in the control plots the number and diversity of species was basically unchanged which statement best explains these results? |. keystone species are critical to the diversity and stability of an ecosystem ||. when a predator is removed the prey of the predator always increases and species not eaten by the predator always decrease |||. the disappearance of producers from an ecosystem can cause the number of predators to increase

A) the enthralling of formation for pure element in its standard state is always positivehope this : )

Answerthis solution will not form a precipitateexplanationsolubility equilbrium:         pbf₂(s)  ⇄ pb²⁺(aq) + 2 f⁻(aq)the solubility product expression is    (we exclude solids from the equilibrium expression).now suppose we have the trial ion product q, which we can define as    then, we can interpret  q as the product of the concentration of the ions that we have and ksp as the product of the ion concentrations that are needed to form a saturated solution.if q > ksp, then that implies that there will be a surplus of ions that exceed the amount that is required to form a saturated solution. a precipitate will then form (the precipitate continually  forms until the surplus ions are removed and q is decreased to ksp's value).if q = ksp, the saturated solution that forms is barely saturated and the precipitate will be minimal.if q < ksp, then the ion concentration will not be enough to form a saturated solution (so no precipitate).using our information, we calculate the trial ion product:     since q = 2.7  × 10⁻⁸ < ksp =  4  ×  10⁻⁸, a precipitate will not form.

The disturbance is only parallel to the motion of the wave.