<h2>Answer:</h2><h3>D. ability to react with oxygen</h3><h2>Explanation:</h2>
<em>Im</em><em> </em><em>not</em><em> </em><em>sure</em><em> </em><em>this</em><em> </em><em>in</em><em> </em><em>your</em><em> </em><em> </em><em>choices</em><em> </em><em>but</em><em> </em><em>if</em><em> </em><em>it</em><em> </em><em>is</em><em>,</em><em> </em><em>this</em><em> </em><em>is</em><em> </em><em>the</em><em> </em><em>answer</em><em>. </em>
<em>I</em><em> </em><em>hope</em><em> </em><em>I've</em><em> </em><em>helped</em><em>. </em>
A) 
The total energy of the system is equal to the maximum elastic potential energy, that is achieved when the displacement is equal to the amplitude (x=A):
(1)
where k is the spring constant.
The total energy, which is conserved, at any other point of the motion is the sum of elastic potential energy and kinetic energy:
(2)
where x is the displacement, m the mass, and v the speed.
We want to know the displacement x at which the elastic potential energy is 1/3 of the kinetic energy:

Using (2) we can rewrite this as

And using (1), we find

Substituting
into the last equation, we find the value of x:

B) 
In this case, the kinetic energy is 1/10 of the total energy:

Since we have

we can write

And so we find:

Spreads out in the medium, first choice
A neutral atom is simply an atom that has no charge.
C decreased the factor cuz the max is smaller